p53 immunostaining pattern in Brazilian patients with hepatocellular carcinoma

Hepatocellular Carcinoma Score and Subclassification Into Aggressive Subtypes Using Immunohistochemical Expression of p53, β-Catenin, CD133, and Ki-67

Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy in adults. Several studies have classified HCC into molecular subtypes aiming at detecting aggressive subtypes. The aim of the present study was to investigate the role of p53, β-catenin, CD133, and Ki-67 in subclassification of HCC into different aggressive subtypes and the correlation between those markers and the clinicopathologic characteristics of HCC patients. This retrospective study was conducted on paraffin-embedded blocks of 114 HCC specimens. Tissue microarray was constructed and immunostaining for p53, β-catenin, CD133, and Ki-67 was performed and HCC score was formulated. P53 expression was associated with old age (P=0.028), large tumor size (P=0.019), poorly differentiated HCC (P=0.012), hepatitis B virus (HBV) positivity (P=0.032), and hepatitis C virus (HCV) negativity (P =0.046). β-catenin expression was associated with small sized tumors (P=0.005), HBV negativity (P=0.027), early-staged tumors (P=0.029), and prolonged recurrence-free survival (P=0.045). High percentage of CD133 expression was associated with old patients (P=0.035) and HBV positivity (P= 0.045). Ki-67 expression was associated with large tumor size (P= 0.049), vascular invasion (P= 0.05), old age (P=0.035), and previous treatment of HCV by direct acting antiviral agents (P=0.005). Cases with high HCC score showed significant association with old patients (P=0.002), previous treatment of HCV by direct acting antiviral agents (P<0.001), large tumor size (P<0.001), and poorly differentiated tumors (P= 0.009). The proposed HCC score can divide HCC patients into subtypes necessitating tailoring of treatment strategy according to this proposed score to target and optimally treat the aggressive subtypes. This score needs to be further validated on large number of patients with longer follow-up period.

The Differential Immunohistochemical Expression of p53, c-Jun, c-Myc, and p21 Between HCV-related Hepatocellular Carcinoma With and Without Cirrhosis

Hepatocellular carcinoma (HCC) constitutes 70.48% of all liver tumors among Egyptians with multifactorial etiology and complex pathogenesis. HCV infection is the most common risk factor of HCC in Egypt, which commonly develops on top of cirrhosis (HCC-C); however, 15% to 20% of HCC are reported to arise in noncirrhotic livers (HCC-NC). This study aimed to explore the differences in the immunohistochemical expression of p53, c-Jun, c-Myc, and p21 between HCC-C and HCC-NC to verify the underlying molecular pathways and to study their role in hepatocarcinogenesis. This study investigated 103 cases of HCC (86 cases of HCC-C and 17 cases HCC-NC including tumorous and nontumorous tissues) together with 10 cases of chronic hepatitis and 10 cases of pure cirrhosis as control groups. Zero, 100%, 100%, and 50% of chronic hepatitis cases were positive for p53, c-Jun, c-Myc, and p21, respectively. All cirrhotic cases were negative for p53 and c-Jun, whereas they were all positive for c-Myc and p21. A total of 41%, 11.65%, 86.4%, and 57.3% of HCC cases showed p53, c-Jun, c-Myc, and p21 expression, respectively. The only difference between HCC-C and HCC-NC was the H-score values of p21 expression, which were higher in HCC-C compared with HCC-NC (P=0.03). HCV-related HCC commonly develops on top of cirrhosis with a minority develops on top of noncirrhotic liver. Only p21 pathway appears to be upregulated in favor of HCC-C than HCC-NC. p53 is considered as a late-event molecular carcinogen, whereas p21 and c-Myc may serve as early-event molecular carcinogen in HCC. The oncogenic role of p21 may be related to its cytoplasmic localization and its promotion of c-Myc expression. Progressive increase in the intensity of c-Myc expression from chronic hepatitis to cirrhosis to HCC may refer to its role as a multistep regulator of hepatocarcinogenesis. The marked reduction of c-Jun in HCC may refer to its tumor suppressor activity.

249 TP53 mutation has high prevalence and is correlated with larger and poorly differentiated HCC in Brazilian patients

Background

Ser-249 TP53 mutation (249^Ser) is a molecular evidence for aflatoxin-related carcinogenesis in Hepatocellular Carcinoma (HCC) and it is frequent in some African and Asian regions, but it is unusual in Western countries. HBV has been claimed to add a synergic effect on genesis of this particular mutation with aflatoxin. The aim of this study was to investigate the frequency of 249^Ser mutation in HCC from patients in Brazil.

Methods

We studied 74 HCC formalin fixed paraffin blocks samples of patients whom underwent surgical resection in Brazil. 249^Ser mutation was analyzed by RFLP and DNA sequencing. HBV DNA presence was determined by Real-Time PCR.

Results

249^Ser mutation was found in 21/74 (28%) samples while HBV DNA was detected in 13/74 (16%). 249^Ser mutation was detected in 21/74 samples by RFLP assay, of which 14 were confirmed by 249^Ser mutant-specific PCR, and 12 by nucleic acid sequencing. All HCC cases with p53-249ser mutation displayed also wild-type p53 sequences. Poorly differentiated HCC was more likely to have 249^Ser mutation (OR = 2.415, 95% CI = 1.001 – 5.824, p = 0.05). The mean size of 249^Ser HCC tumor was 9.4 cm versus 5.5 cm on wild type HCC (p = 0.012). HBV DNA detection was not related to 249^Ser mutation.

Conclusion

Our results indicate that 249^Ser mutation is a HCC important factor of carcinogenesis in Brazil and it is associated to large and poorly differentiated tumors.

Expression of p53 protein in liver and sera of patients with liver fibrosis, liver cirrhosis or hepatocellular carcinoma associated with chronic HCV infection

OBJECTIVES

Hepatitis C virus (HCV) is a major aetiological agent of chronic hepatitis and it leads to the development of liver cirrhosis and hepatocellular carcinoma (HCC). The significances of p53 protein and anti-p53 antibodies levels in HCV genotype IV infected patients with different liver pathology were evaluated.

DESIGN AND METHODS

Immunostaining and western blot based on monospecific anti-p53 antibody were used for the identification of p53 protein in liver tissues and serum samples. The serum levels of p53 protein and anti-p53 IgG antibodies were evaluated using enzyme linked immunosorbent assay (ELISA).

RESULTS

Mild and diffuse p53 cytoplasmic immunostaining was found in liver tissues of patients with liver fibrosis [F1-F3] and liver cirrhosis [F4] in comparison with strong and diffuse p53 cytoplasmic immunostaining in patients with HCC. The target p53 protein was identified in sera of patients with liver fibrosis, liver cirrhosis and HCC at 53-kDa. The detection rate of serum p53 protein increases significantly (p<0.05) with the progression of the liver pathology. However, a significant difference (p<0.05) was only shown between serum p53 protein level of HCC patients and those of other liver pathology. In contrast, anti-p53 IgG antibodies positive rates showed only a significant decrease (p<0.05) in HCC in comparison with liver cirrhosis.

CONCLUSIONS

The serum and cytoplasmic p53 protein expressions were more pronounced in patients with HCC more than liver cirrhosis, and in liver cirrhosis more than liver fibrosis. These results suggest that HCV genotype IV and p53 protein levels may have a role in the development of HCC among Egyptian patients.

Killing of p53-deficient hepatoma cells by parvovirus H-1 and chemotherapeutics requires promyelocytic leukemia protein

AIM: To evaluate the synergistic targeting and killing of human hepatocellular carcinoma (HCC) cells lacking p53 by the oncolytic autonomous parvovirus (PV) H-1 and chemotherapeutic agents and its dependence on functional promyelocytic leukemia protein (PML).

METHODS: The role of p53 and PML in regulating cytotoxicity and gene transfer mediated by wild-type (wt) PV H-1 were explored in two pairs of isogenic human hepatoma cell lines with different p53 status. Furthermore, H-1 PV infection was combined with cytostatic drug treatment.

RESULTS: While the HCC cells with different p53 status studied were all susceptible to H-1 PV-induced apoptosis, the cytotoxicity of H-1 PV was more pronounced in p53-negative than in p53-positive cells. Apoptosis rates in p53-negative cell lines treated by genotoxic drugs were further enhanced by a treatment with H-1 PV. In flow cytometric analyses, H-1 PV infection resulted in a reduction of the mitochondrial transmembrane potential. In addition, H-1 PV cells showed a significant increase in PML expression. Knocking down PML expression resulted in a striking reduction of the level of H-1 PV infected tumor cell death.

CONCLUSION: H-1 PV is a suitable agent to circumvent the resistance of p53-negative HCC cells to genotoxic agents, and it enhances the apoptotic process which is dependent on functional PML. Thus, H-1 PV and its oncolytic vector derivatives may be considered as therapeutic options for HCC, particularly for p53-negative tumors.

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