Expression of mutant p53 protein in hepatocellular carcinoma

Prognostic value of tumor suppressors in osteosarcoma before and after neoadjuvant chemotherapy

Background

Primary bone cancers are among the deadliest cancer types in adolescents, with osteosarcomas being the most prevalent form. Osteosarcomas are commonly treated with multi-drug neoadjuvant chemotherapy and therapy success as well as patient survival is affected by the presence of tumor suppressors. In order to assess the prognostic value of tumor-suppressive biomarkers, primary osteosarcoma tissues were analyzed prior to and after neoadjuvant chemotherapy.

Methods

We constructed a tissue microarray from high grade osteosarcoma samples, consisting of 48 chemotherapy naïve biopsies (BXs) and 47 tumor resections (RXs) after neoadjuvant chemotherapy. We performed immunohistochemical stainings of P53, P16, maspin, PTEN, BMI1 and Ki67, characterized the subcellular localization and related staining outcome with chemotherapy response and overall survival. Binary logistic regression analysis was used to analyze chemotherapy response and Kaplan-Meier-analysis as well as the Cox proportional hazards model was applied for analysis of patient survival.

Results

No significant associations between biomarker expression in BXs and patient survival or chemotherapy response were detected. In univariate analysis, positive immunohistochemistry of P53 (P = 0.008) and P16 (P16; P = 0.033) in RXs was significantly associated with poor survival prognosis. In addition, presence of P16 in RXs was associated with poor survival in multivariate regression analysis (P = 0.003; HR = 0.067) while absence of P16 was associated with good chemotherapy response (P = 0.004; OR = 74.076). Presence of PTEN on tumor RXs was significantly associated with an improved survival prognosis (P = 0.022).

Conclusions

Positive immunohistochemistry (IHC) of P16 and P53 in RXs was indicative for poor overall patient survival whereas positive IHC of PTEN was prognostic for good overall patient survival. In addition, we found that P16 might be a marker of osteosarcoma chemotherapy resistance. Therefore, our study supports the use of tumor RXs to assess the prognostic value of biomarkers.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1397-4) contains supplementary material, which is available to authorized users.

Clinical and pathological analysis of 27 patients with combined hepatocellular-cholangiocarcinoma in an Asian center

BACKGROUND

Our purpose was to assess the clinicopathological features and surgical outcomes of combined hepatocellular-cholangiocarcinoma (HCC-CC) in an Asian center.

METHODS

Between 1998 and 2009, 27 patients were diagnosed with combined HCC-CC at our hospital. Their medical records were reviewed and clinicopathological data retrospectively analyzed.

RESULTS

The 27 patients included 24 (88.9%) males and 3 (11.1%) females with a mean age of 58.26 ± 11.18 years. Cirrhosis was present in 10 patients (37.0%), and 12 patients had hepatitis C or hepatitis B virus infection. Serum alpha fetoprotein was >20 ng/ml in 7 of the 19 patients in whom it was measured (36.8%). Twenty-five patients underwent hepatic resections and 2 received liver transplantations. Five (18.5%) patients had separate HCC and CC within the same liver (type I), 21 (77.8%) had tumors with mixed components (type II), and 1 patient had a type III tumor (3.7%). Of 22 patients with immunohistochemical data, 19 (86.4%) were cytokeratin (CK) 7-positive, 20 (90.9%) were CK19-positive, and 4 (18.2%) were CK20-positive. Mean follow-up was 25.8 months. The 1- and 2-year survival rates were 72.5 and 49.4%, respectively. The 1- and 2-year disease-free survival rates were 54.2 and 41.3%, respectively. Symptoms at the time of diagnosis, and regional lymph node metastases, were associated with higher mortality and recurrence.

CONCLUSIONS

Lymph node metastasis and positive resection margins are important factors affecting HCC-CC surgical outcomes.

Hepatocellular carcinoma: New and emerging risks

The underlying liver diseases that put patients at risk for the development of hepatocellular carcinoma (HCC) are well known. However, it is equally well known that not all patients with these conditions will develop HCC. Therefore within the disease groups (hepatitis B, cirrhosis, etc.,) there are other factors that indicate greater or lesser risk. Some markers of risk are common to all causes of HCC, such as cellular dysplasia, advancing age and male gender. Others factors are specific to individual diseases. This has been well established for hepatitis B in which viral load, genotype and antigen status are major contributors to increased risk of HCC. For both hepatitis B and hepatitis C attempts have been made to identify those individuals at greatest risk using data from large cohort studies. In addition to the common causes of liver disease that are recognized to be causes of HCC non-alcoholic fatty liver disease and possibly diabetes are newly emerging risk factors.

Is p53 gene mutation an indicatior of the biological behaviors of recurrence of hepatocellular carcinoma?

AIM: To evaluate mutant p53 gene in primary hepatocellular carcinoma and to investigate the correlation between it and the recurrence of hepatocellular carcinoma.

METHODS: Mutations of p53 gene were examined using anti-human p53 monoclonal antibody and immunohistochemical staining in 79 resected hepatocellular carcinomas. The correlations among variables of p53 positivity and invasiveness, disease free interval and survival were studied. In addition, in those who developed recurrence, the correlation among p53 positivity, clinical features and post-recurrence survival were also studied.

RESULTS: Of these 79 cases, 64 (81%) had p53 mutation. Those patients with mutant p53 positivity had significantly more tumor recurrence (76.6% vs 40.0%, P = 0.0107). However, the COX proportional hazards model showed that p53 overexpression had only weak correlations with recurrence free interval and survival time (P = 0.088 and 0.081), which was probably related to the short duration of follow-up. The invasiveness variables may be predictors of HCC recurrence. On univariate analysis, more patients with mutant p53 positivity had vascular permeation [78.1 vs 40.0%, P = 0.0088, O.R. (odds ratio) = 5.3], grade II-IV differentiation (98.4 vs 80.0%, P = 0.0203, O.R. = 15.7), no complete capsule (82.8 vs 53.3%, P = 0.0346, O.R. = 4.2) and daughter nodules (60.9 vs. 33.3%, P = 0.0527, O.R. = 3.1) than patients with negative p53 staining. On multivariate analysis, only vascular permeation and grade of differentiation remained significant (P = 0.042 and 0.012). There was no statistically significant correlation between the status of p53 in the primary lesion and the clinical features of recurrent hepatocellular carcinomas examined, including extrahepatic metastasis (P = 0.1103) and the number of recurrent tumors (P = 1.000) except for disease over more than one segment in the extent of recurrent tumors (P = 0.0043). The post-recurrence median survival was lower in patients in whom p53 mutation had been detected in the primary lesion with a weak significance (3.42 mo vs 11.0 mo, P = 0.051).

CONCLUSION: Our findings suggest that p53 mutation correlates significantly with invasiveness including vascular permeation, grade of cellular differentiation, incomplete capsule and multinodular lesions. Hepatocellular carcinomas with p53 mutations had more tumor recurrence and p53 mutation may also influence disease recurrence interval and survival time. Hepatocellular carcinomas with p53 mutations recur more extensively with a shorter survival. Therefore, p53 mutation in the primary lesion is useful as an indicator of the biological behavior of recurrent hepatocellular carcinomas.

p53 mutations in british patients with hepatocellular carcinoma: clustering in genetic hemochromatosis

BACKGROUND & AIMS

Environmental factors are important in the etiology of hepatocellular carcinoma (HCC). Aflatoxin B1 causes a specific point mutation in the p53 tumor-suppressor gene in exposed individuals. In Western populations, mutations of this gene seem to be less frequent. We have investigated the role of p53 mutations in tumorigenesis in British patients with HCC. The aim of this study was to determine the frequency and mutational spectrum of the p53 gene in HCCs from British patients.

METHODS

DNA from 170 HCCs, of well-defined etiology, in British patients was analyzed by single-stranded conformational polymorphism using the polymerase chain reaction technique. Mutations were then characterized by direct sequencing.

RESULTS

Twenty-nine percent of tumors had p53 mutations. Ten of 14 (71%) hemochromatotic cancers had mutations within the p53 gene, and clustering of these mutations at codon 220 (A-G) was found in 5 cases; 3 others had T-A mutations. No clustering was found in HCCs with other etiologies.

CONCLUSIONS

p53 mutations are more common than was thought in Northern European HCCs. This is the first demonstration of p53 mutational clustering in HCCs from hemochromatotic subjects.

Prognostic influence of clinicopathologic features, DNA-ploidy, CD44H and p53 expression in a large series of resected hepatocellular carcinoma in France

Factors affecting outcome after resection of hepatocellular carcinoma (HCC) in patients from Western countries are not clearly defined. Different clinicopathological factors, including DNA ploidy and expression of p53 and CD44H proteins were evaluated retrospectively in 113 patients undergoing curative resection; 11 clinical and 12 pathological factors were studied. Survival curves were calculated by the Kaplan-Meier method and multivariate analysis of outcome predictors for 103 HCC was assessed by Cox regression. By univariate analysis, survival was significantly better in patients with a high serum albumin level >4.0 g/dl, a normal serum alpha-fetoprotein level and an absence of microscopic vascular invasion by the tumor. In multivariate analysis, only high serum albumin level and absence of vascular invasion were found to be independent favorable predictive factors. CD44H expression was significantly correlated with vascular involvement. However, CD44H and p53 expression did not affect survival. The DNA ploidy pattern showed a bimodal distribution, but did not influence the survival rate. This study suggests that pre-operative level of albumin and microscopic vascular invasion can predict long-term survival in patients who have undergone curative resection for HCC. By contrast, the DNA-ploidy pattern and the immunohistochemical detection of p53 and CD44H expression are not predictors of outcome of patients with HCC.

p53 expression in hepatocellular carcinoma in Greece. Correlation with epidemiological and histopathological data

Localization of p53 oncoprotein was investigated in 60 hepatocellular carcinomas (HCCs) from patients resident in the Northwest and Central Greece. The streptavidin-biotin complex immunoperoxidase method was performed in archival formalin-fixed, paraffin-embedded material, using the monoclonal antibody DO-1. The aim of our study was to correlate p53 expression with histological and epidemiological data. p53 overexpression in patients with serological hepatitis B or C was greater (47%) as compared to that observed in patients without these markers (p < 0.01). Morphologically normal liver tissue (NLT) and liver cell dysplasia (LCD) was recognized adjacent to HCC developing on non-alcoholic cirrhotic livers in patients with "NonA, NonB hepatitis" from between 1975-1986. NLT and LCD and p53 oncoprotein was expressed in 10% of the cases. No relationship was observed between p53 expression and tumor histological grade, patients' age and sex. These results suggest that in Northwest and Central Greece, p53 oncosupressor gene may be involved in some HCCs; it may be associated with viral chronic infection disease (HBV or HCV), and as yet with uncharacterized viruses which remain to be determined.

Mutations of the p53 tumor suppressor gene and ras oncogenes in aflatoxin hepatocarcinogenesis

Aflatoxin B1 (AFB1) is classified as a group I carcinogen in humans by IARC. However, the exact mechanisms of AFB1 hepatocarcinogenesis have not been fully elucidated. Recent studies have suggested that oncogenes are critical molecular targets for AFB1, and AFB1 causes characteristic genetic changes in the p53 tumor suppressor gene and ras protooncogenes. Up to date, more than 1500 human hepatocellular carcinoma (HCC) samples have been examined for p53 mutations with respect to different AFB1 exposure levels. The most significant finding is that more than 50% of HCC patients from high aflatoxin exposure areas such as southern Africa and Qidong, China harboured a codon 249 G to T transversion in the p53 tumor suppressor gene, which is found to be consistent with the mutagenic specificity of AFB1 observed in vitro. In contrast, this mutational pattern is not found in HCC samples from moderate or low aflatoxin exposure countries or regions. Therefore, this hot-spot mutation is believed to be a molecular fingerprint linking the initial event of AFB1-DNA adduct formation with the ultimate development and progress of human HCC. However, some important points still remain to be explicated. First, in many of these studies, the systematic evaluation of AFB1 exposure is rather limited and the classification of AFB1 exposure level is speculative and confusing, without the definite evidence for the actual aflatoxin exposure level. Second, the role of hepadnaviral infection has to be considered in the induction of this unique mutational spectrum. On the other hand, ras oncogene mutations are frequently found in AFB1-induced HCC samples in experimental animals, while the frequency of ras mutation in human HCC in contrast is much lower than that of p53. Recent studies have provided additional evidence that reactive oxygen species (ROS) and oxidative DNA damage may be involved in AFB1-induced p53 and ras mutations. In future, follow-up cohorts exposed to different levels of AFB1 combined with the determination of putative gene markers are much needed.

Hepatocellular carcinomas with a high proliferation index and a low degree of apoptosis and necrosis are associated with a shortened survival

In this study we investigated tumour growth in relation to the immunohistochemical expression of p53 and bcl-2 and to patient survival data in 33 operated hepatocellular carcinomas (HCCs). In order to estimate the growth, a growth index, based on the degree of cell proliferation, apoptosis and necrosis, was calculated for each tumour. Cell proliferation was determined immunohistochemically by the number of proliferating cell nuclear antigen (PCNA)-positive cells in tumours, the extent of apoptosis was determined by counting the number of cells labelled by the in situ 3'-end labelling technique and tumour necrosis was estimated as the percentage of necrotic areas in haematoxylin--eosin-stained tissue sections. In our analysis we found that the survival of patients with HCCs showing a high growth index (i.e. tumours showing a high proliferation and simultaneously a low degree of apoptosis and necrosis) was significantly shorter than with other patients (P = 0.004, log-rank test). When analysed separately, cell proliferation, apoptosis or necrosis did not show any significant association with survival. p53 positivity was found in 8/33 (24%) of tumours. There were significantly more p53-positive cases in tumours with a high growth index (P = 0.01, Fisher's exact test) suggesting that dysfunction of the p53 gene may affect tumour growth. p53-positive cases did not, however, have a significantly shorter survival time than p53-negative cases (P = 0.3, log-rank test). bcl-2 positivity was found in only 1/33 (3%) of the HCCs. Thus bcl-2 overexpression does not seem to play an important role in hepatocellular carcinogenesis. In summary, our results suggest that in HCCs a compound score based on the evaluation of the degree of cell proliferation, apoptosis and necrosis is a biologically more relevant prognostic indicator than any of its composite parameters alone.

Alpha-fetoprotein and p53 autoantibodies in patients with chronic hepatitis C

Hepatitis C virus infection is a common cause of chronic liver disease and hepatocellular carcinoma. Recently, mutations in the p53 tumor suppressor gene with generation of circulating autoantibodies to p53 protein have been detected in a significant proportion of patients with different malignancies. Using ELISA methods we assessed alpha-fetoprotein and anti-p53 as serological screening parameters for hepatocellular carcinoma in 147 consecutive patients with chronic hepatitis C. Liver cirrhosis was histologically diagnosed in 58 patients (39.5%) and a hepatocellular carcinoma confirmed in seven patients (4.8%). Serum alpha-fetoprotein was raised above 20 ng/ml in 26/147 patients and above 100 ng/ml in 5/147 patients. In 6/7 patients with hepatocellular carcinoma, alpha-fetoprotein was raised above 20 ng/ml, but only in 3/7 cases above 100 ng/ml, resulting in a sensitivity and specificity of 85.7% and 85.7% (alpha-fetoprotein > 20 ng/ml) and 42.9% and 98.6% (alpha-fetoprotein > 100 ng/ml) for the detection of hepatocellular carcinoma, respectively. Autoantibodies to p53 were detected in 3/7 patients with hepatocellular carcinoma, but in 0/140 patients without malignancy (sensitivity 42.9%, specificity 100%). Screening for hepatocellular carcinoma was improved by combining alpha-fetoprotein measurement (level > 100 ng/ml) with detection for anti-p53 (sensitivity 71.4%, specificity 98.6%). In conclusion, the presence of anti-p53 was highly specific for malignancy and independent of alpha-fetoprotein status. Further studies including a larger number of patients with hepatitis C virus-related hepatocellular carcinoma are required to investigate whether serological testing for anti-p53 in combination with alpha-fetoprotein might improve the detection of hepatocellular carcinoma in high-risk patients with liver cirrhosis.

p53 expression in patients with cirrhosis with and without hepatocellular carcinoma

BACKGROUND

Mutated p53 acts as a dominant oncogene, whereas the wild type (wt) p53 gene product suppresses cell growth. Abnormalities in the p53 gene are reported in more than 50% of malignant tumors. Recently, an allelic loss of chromosome 17p, where the p53 gene is located, was found to be more frequent in hepatocellular carcinoma (HCC) cell lines and human tumors. In addition, in half of the cases of HCC from endemic areas for hepatitis B virus and aflatoxin, a hot spot point mutation at codon 249 was detected, as previously reported. Missense mutations in p53, mdm-2 complex formation, and other unknown mechanisms may lead to stabilization of the gene product, thus rendering it detectable by immunohistochemistry.

METHODS

To assess the relationship between p53 status at a premalignant stage and in HCC, the authors studied the immunohistologic expression of p53 in HCC and in the adjacent nontumorous resected liver tissue, using monoclonal antibody to wt and mutated p53.

RESULTS

Twelve of the 14 patients with liver tumors had HCC. Of the 12 patients with HCC and underlying cirrhosis, 8 (67%) had increased p53 expression in HCC cells. Eight of the 12 patients with p53-positive HCC cells had p53 overexpression in the nontumorous hepatocytes within regenerative nodules adjacent to HCC tissue. Three of 21 cirrhotic livers without a detectable tumor had increased p53 expression in the regenerative nodules. None of the 12 patients with chronic active hepatitis without cirrhosis or the 13 with a normal liver histology had increased p53 expression.

CONCLUSION

p53 overexpression in some cirrhotic livers and in nontumorous livers of patients with HCC may indicate a normal p53 gene response to cellular stress or, alternatively, to an abnormally or mutated p53 gene, and could occur before the development of HCC.

p53 expression in hepatocellular carcinoma in a population in Singapore with endemic hepatitis B virus infection

AIMS

To study the expression and clinical significance (if any) of p53 protein in hepatocellular carcinomas (HCC) arising in a population with endemic hepatitis B virus (HBV) infection.

METHODS

Immunohistochemical staining was performed on formalin fixed, paraffin was embedded histological sections of 46 HCC cases using an antihuman p53 monoclonal antibody; serial sections were also stained for hepatitis B surface antigen (HBsAg), hepatitis B core antigen (HBcAg) and alpha fetoprotein (AFP). Nuclear p53 staining was assessed according to intensity (absent, weak or strong) and extent (< 5%, 6-25%, 26-50%, and > 50%) of positive cells. Tissue HBsAg, HBcAg and AFP were recorded as absent or present.

RESULTS

The p53 protein was expressed in 35% (16 of 46) of HCCs; the positive rate in grade III/IV tumours (13 of 31; 42%) was higher than in grade I/II tumours (three of 15; 20%) but this was not statistically significant. HBsAg positive tumours showed almost the same proportion of p53 staining (11 of 29; 38%) as HBsAg negative ones (five of 17; 29%).

CONCLUSIONS

The p53 protein was expressed in 35% of HCC cases. There was no statistically significant correlation between HBV infection and p53 protein expression. Similarly, there was no definite correlation between p53 positivity and tumour size, histological grade or vascular invasion.