|
 
 |
| REVIEW ARTICLE |
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| Year : 2023 | Volume
: 3
| Issue : 1 | Page : 6-13 |
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Clinicopathological progress of dual-phenotype hepatocellular carcinoma
Lei Li1, Guangjie Liao2
1 Department of Pathology, Affiliated Hospital of Youjiang Ethnic Medical University, Baise, China
2 Department of Pathology, Red Cross Hospital of Yulin, Yulin, China
| Date of Submission | 14-Nov-2022 |
| Date of Decision | 19-Dec-2022 |
| Date of Acceptance | 21-Dec-2022 |
| Date of Web Publication | 16-May-2023 |
Correspondence Address:
prof. Guangjie Liao
Department of Pathology, Red Cross Hospital of Yulin, No. 1, Jin Wang Road, Yuzhou, Yulin, Guangxi Province
China
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/aort.aort_32_22
Clinicopathological progress of dual-phenotype hepatocellular carcinoma (DPHCC) is a new subtype of hepatocellular carcinoma with poor prognosis. Immunohistochemistry plays a key role in the diagnosis of DPHCC. DPHCC is closely related to the mechanism of epithelial-mesenchymal transition and the stem cell characteristics of tumors. At present, there were few relevant literatures. We review the clinicopathological progress of DPHCC.
Keywords: Dual-phenotype hepatocellular carcinoma, clinicopathology, immunohistochemistry, research progress
How to cite this article:
Li L, Liao G. Clinicopathological progress of dual-phenotype hepatocellular carcinoma. Ann Oncol Res Ther 2023;3:6-13 |
How to cite this URL:
Li L, Liao G. Clinicopathological progress of dual-phenotype hepatocellular carcinoma. Ann Oncol Res Ther [serial online] 2023 [cited 2023 May 31];3:6-13. Available from: http://www.aort.info/text.asp?2023/3/1/6/376896 |
| Introduction | |  |
Primary liver cancer is one of the malignant tumors with the highest incidence both in the world and in China. Histologically, it could be divided into hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC), and combined hepatocellular carcinoma (CHC).[1] HCC and ICC accounted for 80% and 15% of primary liver cancer, respectively.[2],[3] CHC is a rare type, accounting for 1.0%–14.2% of primary liver cancer.[4] Dual-phenotype hepatocellular carcinoma (DPHCC) was first reported in the literature in 2011, accounting for 10% of HCC.[5] Currently, DPHCC is being considered a new special subtype of HCC. In recent years, there has been a slight increase in the research literature on DPHCC, and its genomic characteristics have been explored in the latest literatures.[6] DPHCC is different from morphologic regions of the coexistence of the classical HCC and ICC in a single nodule of CHC. DPHCC refers to the typical polygonal HCC cell morphology and sinus cord structure in the same tumor region, expressing one or more HCC markers (such as HepPar-1 and GPC-3) and one or more ICC markers (such as CK19, CK7, MUC-1, CA19-9, and CEA). DPHCC has the dual-biological behavior of HCC and ICC because of its double open gene, thus it is worse differentiation, higher probability of microvascular invasion (MVI), and metastasis, and it may be higher risk of recurrence, worse clinical prognosis, and more intractable treatment. Its overall survival (OS) and disease-free survival (relapse-free survival [RFS]) are significantly lower than those of common type HCC.[5] In terms of diagnosis, DPHCC is difficult to distinguish from classical HCC because of its typical morphological characteristics, which may show high-grade (poorly differentiated) HCC, and can only be distinguished by immunohistochemistry at present. In this review, the epithelial-mesenchymal transition (EMT) mechanism of HCC is closely related to the stem cell characteristics of the tumor, this is the reason why the poor prognosis of DPHCC, among which ICC markers and stem cell markers may play an important role. The review intends to review the progress of research on ICC markers and SALL4 with their possible synergistic effects in the clinical prognosis of DPHCC.
This review has been conducted in accordance with the guidelines provided by the Declaration of Helsinki on Ethical Principles for Medical Research Involving Humans.
| Research Progress of Intrahepatic Cholangiocarcinoma Marker and SALL4 with Their Synergistic Effect in the Diagnosis and Prognosis of Dual-phenotype Hepatocellular Carcinoma | | |
Clinicopathological features of dual-phenotype hepatocellular carcinoma
There were no significant differences in clinical characteristics such as age of onset, history of viral hepatitis, and serum alpha-fetoprotein (AFP) changes in patients with DPHCC compared to common type HCC. Some DPHCC patients might have elevated levels of serum AFP and CA19-9, respectively, or both, which may be related to the presence of both AFP- and CA19-9-related genes in DPHCC cells. This clue supported DPHCC as a subtype of HCC. In contrast, the OS rate and RFS rate of DPHCC patients were significantly lower than those of common HCC patients, which also suggested that there were differences in the regulatory genes between the two groups. DPHCC shows typical morphological features, such as most of the cells are arranged into normal lamellar sinusoidal cordlike structure, separated by hepatic sinusoids polygonal shape, and abundant bisphilic cytoplasm, and the cells could also be hyaline and steatosis. Some DPHCCs may show high-grade HCC. Therefore, it is impossible to distinguish DPHCC from common type HCC by histological morphology, and its diagnosis must rely on immunohistochemistry at present.[5],[7],[8],[9] Current diagnostic criteria are that the primary liver tumor has a single HCC cell morphology and that more than 15% of the cancer cells are strongly sensitive to one or more hepatocellular markers (e.g., HepPar-1). GPC-3 was strongly positive and mainly dispersed. More than 15% of the cancer cells are positive for one or more hepatocyte markers and one or more cholangiocarcinoma markers are positive for membrane and/or cytoplasm. In particular, DPHCC should be excluded when HCC tumors are of high grade/poorly differentiated.[5] Because HCC masses are often large and have a high degree of tumor heterogeneity, biopsy tissue does not diagnose DPHCC, which often leads to false negatives. If the tumor tissue has both HCC and ICC morphology, it could not be diagnosed as DPHCC. Attention should be paid to the identification of HCC and Use mixed hepatocellular cholangiocarcinoma (CHC), which is different from DPHCC in both morphology and immunohistochemistry. CHC has its own histological morphology and separately expresses protein markers of HCC and ICC.[10]
In the study[11],[12] with large sample of HCC, DPHCC accounted for about 10% of HCC. The prognostic indices of DPHCC, such as liver capsule invasion, tumor satellite foci, and the incidence of MVI, were higher, and the OS and RFS of DPHCC patients were significantly lower than those of patients with common HCC; this tip proved that the expression of CK19 was positively correlated with MVI and other risk factors of HCC. In other multicenter studies,[13],[14] the incidence rates of intrahepatic metastasis, MVI, abdominal lymph node metastasis, and distant organ metastasis in CK19-positive HCC were more common, and the OS and RFS were also significantly higher than CK19-negative HCC. Compared with CK19-negative HCC, the 5-year survival rate of liver transplantation patients with CK19 positive was lower, which provided a valuable reference for the selection of CK19-positive patients when liver transplantation.
There may be high-frequency mutations in key genes of DPHCC. Whether abnormal expression of these key genes leads to worse prognosis remains to be elucidated. The TCGA database of HCC samples can be used to evaluate the expression of markers based on gene expression, and copy number variants leading to changes in HCC subtypes still need to be validated in larger cohorts. Most of the mutated genes did not show abnormal expression, Most of the mutated genes did not show abnormal expression due to the limited sample size of studies, which shows the inability to accurately reflect its relevance. More data and larger cohort studies are needed to explore exactly which gene mutations lead to aberrant expression and ultimately worsen tumor progression. It was not possible to assess whether they co-expressed both markers and the proportion of tumor cells.
Significance of bile duct epithelial markers in the occurrence of dual-phenotype hepatocellular carcinoma
Immunohistochemistry is the main method for clinicopathological differentiation between DPHCC and common HCC. CK19, CK7, MUC-1, CA19-9, and CEA are all markers of ICC, among which CK19 has received more attention in the literatures. CK19 is an intermediate filament with a molecular weight of about 40 kDa. During embryonic development, CK19 is detected in primitive liver progenitor cells between 4 and 10 weeks of gestation. With the development of fetal liver, primitive hepatic progenitor cells (HPCs) differentiate bidirectionally into hepatocytes or bile duct epithelial cells.[15] However, CK19 is not expressed in mature hepatocytes but always exists in bile duct epithelial cells.[15],[16],[17] This explains why CK19 has become an important marker of biliary epithelial cells in pathological diagnosis.[18],[19],[20]
When hepatocytes are damaged in various chronic liver diseases (e.g., chronic hepatitis, alcoholic steatohepatitis, and hemochromatosis), previously quiescent normal hepatocytes become activated and turn into progenitor cells,[6],[21],[22] and CK19 reappears in hepatocytes. Furthermore, a large number of studies have shown that CK19 also appears abnormally in liver cancer, with an incidence between 10% and 30%.[23],[24],[25],[26]
Compared with other bile duct epithelial markers, CEA is one of the most commonly used markers for pathological diagnosis of bile duct epithelial-derived tumors. HepPar, CEA, CK19, MUC-1, and CA19-9 in DPHCC were 89.7%, 91.0%, 80.6%, 38.7% and 2%, respectively, and these are commonly used marker for diagnosis of hepatocellular tumors. CK19 has been extensively studied in the literature in DPHCC. The positive rates of HepPar, CEA, CK19, MUC-1, and CA19-9 in DPHCC were 89.7%, 91.0%, 80.6%, 38.7%, and 20.7%, respectively. The combination of these markers can improve the diagnosis rate of DPHCC.[1],[27] HCC may occur from hepatic precursor cells/stem cells. CK19 and/or CA19-9, CK7, and MUC1 may be markers of hepatic precursor cells/stem cells at different stages. Kim et al.[27] found that CK19-positive HCC expressed at least one liver progenitor cell (HPC) marker, such as EpCAM, ckit, CD133, and other proteins, suggesting that CK19 might have the highest specificity and sensitivity compared with other markers. Both CK19 and AFP are expressed in oval cells of small bile ducts with hyperplasia adjacent to HCC. These oval cells are liver tumor stem cells. Therefore, the combination analysis of CK19 and AFP may have more clinical value in indicating the presence of oval cells and the origin of DPHCC, and the combination analysis of multiple bile duct markers may improve the specificity and sensitivity of DPHCC. Kawai et al.[28] found that the expression of CK19 in HCC was closely related to glucose transporter 1 and fludeoxyglucose (FDG), and fluorine-18 FDG positron emission tomography or Gd-EOB-DTPA-MRI imaging detection method could be used[29] to evaluate the expression of CK19 in DPHCC and provide new therapeutic targets.
There has been some progress in the molecular mechanism of the correlation between CK19 and prognosis of DPHCC. There have been several genes with different mutations in DPHCC and CK19-positive HCC at the same time including ABL1, E4F1, PEAK1, TADA3, INPP5D, S1PR4, and GOLM1.[6] ABL1 is a proto-oncogene involved in the encoding of a variety of cellular protein tyrosine kinases.[30] E4F1, a transcription factor in the Gli-Kruppel family, is a multifunctional protein with transcriptional and atypical ubiquitin E3 ligase activities, which plays a role in cell survival and proliferation.[31] PEAK1 is involved in the regulation of cell migration, proliferation, and cancer metastasis,[32],[33],[34],[35] while TADA3 is involved in stabilizing and activating p53 and plays a role in the cellular response to DNA damage.[36] Mutations in INPP5D are associated with defects in the immune system and cancer.[37] S1PR4 may be involved in specific cell migration processes.[38] GOLM1 is associated with the development of liver disease. It can be used as a marker of liver injury,[39] and it has been suggested as a potential serum marker for the diagnosis of HCC.[40] The TCGA database of Wang et al.[6] found that the high expression of CK19 was associated with the upregulation of GOLM1, and the poor prognosis of DPHCC could be associated with the activation of PI3K-Akt signaling pathway mutation and the significant downregulation of CXCL9 expression in DPHCC tissues. Compared with common HCC, chromosome 11 of DPHCC is relatively stable, while chromosomes 1q and 8q mostly show CN gain. The frequent variation of the CN gain of TPR and ODR4 on chromosome 1q may indicate that the CN gain of TPR and ODR4 plays a role in the progression of DPHCC, while chromosome 11 has little effect on the transformation of this subtype.
Studies have also found that HCC overexpressing CK19 mRNA also overexpressed Snail, Twist, and other EMT-related genes.[6],[41] Govaere and Kawai[42],[43] found that CK19 could promote the activation of EMT and TGFβ/Smad pathways, and CK19-positive HCC overexpressed bile duct epithelial cell markers such as CD133. DPHCC is resistant to commonly used chemotherapy drugs, such as 5-fluorouracil (5-FU), doxorubicin, and sorafenib, while the knockdown of CK19 gene decreases the resistance, which may be related to TGFβR1 inhibitor pathway. According to the above studies, CK19 can be used as a new target for DPHCC-targeted therapy. As mentioned above, low expression of CXCL9 often appeared in DPHCC, resulting in its poor prognosis. The mechanism may be that the CXCL9 affected the immune microenvironment and hence the prognosisdules of DPHCC.[6]
Significance of SALL4 in the occurrence of dual-phenotype hepatocellular carcinoma
SALL4 is expressed at high levels in fetal liver progenitor cells but not in adult hepatocytes, and it plays a key role in hepatocyte lineage stereotyping. Recently, the SALL4 gene has been identified as a marker of subtypes with progenitor cell-like features (such as CK19+ HCC and DPHCC), and it has been proven to be associated with poor prognosis.[21],[22] The research on SALL4 signaling pathway has made significant progress. SALL4, a human homolog encoding a C2H2 zinc finger transcription factor, is one of the key factors in maintaining pluripotency and embryonic stem cell self-renewal, possibly achieved by the interaction of Oct4, Sox2, and Nanog. SALL4 has two isotypes, SALL4A and SALL4B, and recent studies have shown that SALL4B plays an important role in maintaining stemness of ES cells.[16] The possible mechanism of SALL4 in HCC is that SALL4 affects phosphatase and PTEN and PI3K-AKT signaling in tumor cells through its interaction with NuRD and HDAC complex. Since SALL4 is a known inhibitor of PTEN, silencing of SALL4 can reduce pAKT levels and block PI3K survival signaling in HCC. In addition, SALL4-positive HCC tended to exhibit high HDAC activity and high chemical sensitivity to HDAC inhibitors such as octanoate diisohydroxamic acid and octanoylanilide isohydroxamic acid. HDAC inhibitors play a role by inhibiting the deacetylation of NuRD histones, which may be useful for the treatment of SALL4 positive HCC.[44] SALL4 may be a candidate therapeutic target for HCC.
Invasion and metastasis are important biological characteristics of malignant tumors with poor prognosis. Current studies have believed that EMT is an important mechanism of invasion and metastasis of cancer. The study of molecular markers of EMT in various cancer cells, especially liver cancer cells, may be a key hotspot. Studies have found that EMT is closely related to stem cell markers, and stem cell factors can induce EMT, thereby enhancing invasiveness of tumor cells and drug resistance, leading to tumor metastasis and recurrence.[27],[28] As mentioned above, the progenitor cell marker SALL4 is one of such stem cell factors, especially in hematological malignancies, which can lead to leukemia. The expression of SALL4 may decrease gradually in the mature liver of rat, and becomes silent in adult.This appearance suggests that SALL4 plays an important role in promoting fetal liver development from early to middle stage.[13] Studies have found that SALL4-positive solid tumors were subtypes with stem cell characteristics. Overexpression of SALL4 can induce cancer cells to produce stem cell characteristics, which cause EMT. It is well known that vimentin is a typical marker of mesenchymal cells, while E-cadherin is an epithelial marker. Studies have found that interference with SALL4 gene can lead to the increase of E-cadherin mRNA and its protein products, and the decrease of Vimentin mRNA and its protein products. Silencing of SALL4 gene can prevent the occurrence of EMT in cancer cells and reduce the invasion and invasion ability. Studies found that the expression of SALL4 protein is increased in some HCC cells.[12] Progenitor subtypes in HCC are generally considered to have a poor prognosis. It is speculated that the re-expression of SALL4 in DPHCC is a marker of the transition from normal hepatocytes to cancer cells. The expression of SALL4 in stem cells promotes the occurrence of DPHCC and other HCCs with stem cell phenotype, which also confirmed that SALL4 may contribute to the poor prognosis of DPHCC through EMT mechanism.[45],[46]
Relationship between CK19 and SALL4 in dual-phenotype hepatocellular carcinoma and its role in dual-phenotype hepatocellular carcinoma
As mentioned above, CK19 is detected in primitive liver progenitor cells during early pregnancy. With the development of fetal liver, these progenitor cells differentiate bidirectionally into hepatocytes and bile duct epithelial cells. CK19 gradually loses its expression in mature hepatocytes but persists in bile duct epithelial cells. When resting cells are activated in response to inflammation or other stimuli, CK19 can be activated and reappear on hepatocytes again. CK19 is also abnormally present in some HCC cells. SALL4 showed a similar performance in animal experiments. In the liver of rats, the expression of SALL4 gene gradually decreased as the liver grew up and was silenced after adulthood, while expression of the protein product of the SALL4 gene is increased in some HCCs. This suggests that there may be relation between CK19 and SALL4 in some HCCs.
At present, there were few studies on the relationship between CK19 and SALL4 in DPHCC. Kawai T et al.[43] confirmed that SALL4 was highly expressed in fetal and infant hepatocytes, and its protein products were positive in 17 out of 20 HCC patients, whereas it was not detected normal hepatocytes and cholangiocytes of adults. There existed a higher probability of moderate to poorly differentiated histology and a higher frequency of microvascular or macrovascular invasion (72.3%) and intrahepatic metastasis (34.0%) in SALL4-positive HCC. Immunohistochemical expression for CK19 and EpCAM was higher in Sall4-positive HCC (42.6% and 51.1%, respectively) and then in SALL4-negative HCC. In the majority of the double-positive cases, the SALL4-positive and CK19-positive regions overlapped at least partially (18/20 = 90.0%). Similar overlapping regions were observed in most SALL4- and EpCAM-positive cases (23/24 = 95.8%).[41] Similar to CK19-positive HCC, SALL4-positive HCC is more aggressive in biological behavior than SALL4-negative HCC.[47],[48] Takano et al.[49] found that the expression of SALL4 can induce the expression of CK19 and EPCAM. The mechanism was that E-cadherin was upregulated after interfering with CK19 gene silencing gene expression and downregulation of vimentin and vascular endothelial growth factor (VEGF), VASH1, VASH2, and FGFR1. This suggested that CK19 and SALL4 might play an important role in promoting the differentiation of liver stem cells into bile duct cells.[49] These studies suggest the mechanism of EMT and angiogenic factors in HCC. They also prompt that CK19 and SALL4 may be synergistic, and they can be considered important therapeutic targets for HCC.
SALL4 is an important transcription factor. It has been reported that the expression of SALL4 can upregulate the expression levels of CK19 on both mRNA and protein.[50] SALL4 is expressed in HCC related to stem cell nature and 5-FU resistance.[51] The investigators proposed that SALL4 might act by binding to the promoter site of CK19. Two member families of Kruppel-like factors (KLF4 and KLF10), which are DNA transcription regulators, are associated with the expression of CK19. Brembeck and Rustgi of the University of Pennsylvania had demonstrated that the CK19 gene was regulated by KLF4 and SP-1.[52] On the other hand, Mi F et al.[53] found that CK19-positive tumors were mainly characterized by KLF10 overexpression in the rat model. Because the murine CK19 gene shows high homology to human CK19,[54] similar findings may also be present in human tumors. In addition, KLF10 had been shown to be a tumor suppressor gene and had been shown to be associated with TGFβ/Smad signaling pathway,[55] and they hypothesized that KLF10 might act by suppressing the CK19 promoter by inhibiting TGFβ/Smad signaling. Other transcription factors such as AP-1, SP-1, SALL4, and the KLF family (KLF4 and KLF10) were also proposed to bind to the CK19 promoter to regulate CK19 expression directly or indirectly.
| The Origin of Dual-phenotype Hepatocellular Carcinoma and Its Relationship with Microenvironment and Traditional Treatment Methods | | |
Relationship between the origin of dual-phenotype hepatocellular carcinoma and hepatic microenvironment changes
The origin of DPHCC is still unclear. Given the biphenotypic characteristics of DPHCC, as discussed above, DPHCC may be derived from HPCs. In practice, we found that the tumor heterogeneity of most DPHCCs is more obvious than that of ordinary HCCs. Wu et al. found that CK19-positive HCC originated from HPC, which was a primitive component in normal liver and expresses HEP and CK19.[56] When liver tissue is injured, quiescent progenitor cells/stem cells can be activated,[57] and hepatocytes can also dedifferentiate into immature progenitor cells or bile duct-type cells.[58],[59] Abundant evidence had shown that these activated HPCs can progress to HCC.[60],[61],[62] Some studies[63] acting with the gene integration of adult hepatocytes from rat fetuses and human HCC divided HCC into two subtypes (HB and HC), and they found that the expression of CK19 was significantly increased in HB subtypes, and also proved that HB subtypes of HCC originated from biphenotypic liver progenitor cells, indicating that CK19-positive HCC derived from HPC. Researchers of Columbia University[64] have also demonstrated that HCC cells were derived from HPCs.
Patients with chronic liver disease are more likely to develop liver cancer due to chronic inflammatory reaction and continuous hepatocyte destruction, repair, and regeneration.[65] Various pathophysiological changes in the long-term inflammatory process can trigger the initiation and promotion of HCC.
The accumulation of genomic instability can be accelerated through genetic and epigenetic changes, expansion of resident liver stem/progenitor cell populations, and changes in liver microenvironment. As mentioned above, chronic liver disease can induce the activation and proliferation of HPC. The recruitment, proliferation, and development of HPC are tightly regulated by various factors transmitted around stem cells, which are referred to as special microenvironment.[66] The hepatic microenvironment is greatly changed, including increased expansion of HPC and sinusoidal endothelial progenitor cells, infiltration of the liver by lymphocytes, and activation of hepatic fibroblasts, leading to scar formation and fibrosis. These dynamic physiological conditions can jointly influence HCC by supporting the development of liver cancer stem cell (CSC). Compared with normal fibroblasts, cancer-related fibroblasts (CAFs) have stronger self-renewal ability and they can increase the secretion of various growth factors, such as CXCL12, hepatocyte growth factor, platelet-derived growth factor, and VEGF, which can promote tumorigenesis.[67] Multiple growth factors or cytokines secreted by endothelial cells and CSC in the tumor microenvironment can promote the transformation of normal fibroblasts into CAF.[68],[69] Mesenchymal stem cells (MSCs) are involved in promoting the growth, invasion, metastasis, angiogenesis, and immunosuppression of cancer cells in the tumor microenvironment by secreting a variety of growth factors, cytokines, chemokines, and extracellular matrix.[70],[71] Mi and Gong found that MSCs secreted large amounts of IL-6 and subsequently promoted the invasion of HCC by activating IL-6/STAT3 signaling.[53] The chronic inflammatory microenvironment of tumor, such as lymphocytic infiltration, can cause the release of inflammatory molecules and the formation of free radicals of oxygen, leading to DNA damage and other pressure to stimulate tumor growth,[72] which can promote the growth, invasion, and metastasis of tumor cells.[73]
Influence of stem cell characteristics of dual-phenotype hepatocellular carcinoma on chemotherapy/radiotherapy
It is well known that CSCs exhibit a variety of epigenetic alterations, which are related to the resistance of HCC to classical therapies such as chemotherapy and radiotherapy.[74] These alterations include dysregulation of ATP-binding cassette (ABC) membrane transporters, cell cycle arrest, enhanced DNA repair, and resistance to anticancer agents.[75] Radiotherapy and many types of chemotherapeutic drugs act by inducing the destruction of DNA in cancer cells. It is hypothesized that the CSC resistance may be due to the increased expression of DNA repair-related genes, such as BRCA1 and RAD51.[76] DNA damage checkpoint protein kinase is one of the most effective modulators of CSC resistance to DNA-damaging chemotherapy drugs, which can activate and delay cell cycle progression through genotoxic stress, thereby promoting DNA repair.[77] Ma et al. found that increasing the expression of CD133 could enhance the sensitivity of HCC to radiotherapy.[78] Another important modulator of the DNA repair system against endogenous and exogenous stem cell DNA damage is the ABC transporter, which selectively extrudates a variety of toxic substrates, resulting in multidrug resistance.[79] Fung et al. it was found that increased expression of ABC transporter was significantly associated with chemotherapy resistance and EMT in HCC.[80] PI3K/Akt is one of the most effective survival signal transduction pathways, contributing to the maintenance and survival of CSC and inducing endogenous drug resistance of CSC.[81] A study of Kahraman et al. showed that PI3K/Akt/mTOR pathway mediated resistance to rapamycin and sorafenib in CD133-positive/EPCAM-positive HCC.[82] TNF-associated apoptosis-inducing ligand (TRAIL) plays an important role in cancer therapy by inducing selective apoptosis of cancer cells, while has little effect on normal cells.[83] Zhu et al. It was seen that TRAIL mediated drug resistance in various hepatic CSC models (such as PLC, HepG2, and Huh7 LC cells) was mediated through PI3K/Akt/ Bad signaling cascade.[84] Another promising target molecule for inducing apoptosis in CSCs is nuclear factor-κB (NF-κB), known as an anti-apoptotic signaling transcription factor, which can be activated by various chemical agents, including sorafenib.[85] Zou et al. showed that sorafenib-induced NF-κB activation contributes to enhancing the resistance of CD133-positive hepatic CSC to sorafenib.[86] These findings suggest that DPHCC with the same stem cell characteristics should have the same mechanism of drug resistance or reduced sensitivity in corresponding chemotherapy and radiotherapy.
| Conclusion | | |
It is believed that in the near future, DPHCC will be recognized by the WHO as a new subtype of HCC with stem cell characteristics due to its different pathological basis and worse clinical prognosis compared with common HCC. The classification of DPHCC can improve the clinical understanding of HCC and improve the efficiency of diagnosis and treatment. Current studies have confirmed that ICC markers, such as CK7, MUC1, and CK19, are important molecular features of DPHCC. These markers may be related to the activation and inhibition of EMT and other related signaling pathways. The activation of these markers enhances the proliferation activity, invasiveness, and poor clinical prognosis of DPHCC. In addition, the abnormal expression of SALL4 in HCC suggests that it may be closely related to the pathogenesis and progression of HCC. Moreover, SALL4 and ICC markers may have synergistic effects, and it is believed that they may also become the therapy targets of DPHCC.[41],[87],[88],[89] HCC is the so-called king of cancers, indicating that its efficacy is still very limited. Therefore, the in-depth study of the histological heterogeneity, biological behavior, progression mechanism, and new treatment strategies of DPHCC is of great value to improve the diagnosis and treatment.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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