الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 225 |  |  |
| | | from | 225 | | |
Abstract
Hepatocellular carcinoma (HCC), the most frequent type of primary liver cancer, is the sixth most common solid tumor and the third cause of cancer mortality in world population, with an alarming increase in its incidence in Egypt, which is now three times higher than that in the USA (Lehman et al., 2008). Liver cirrhosis is the main risk factor for HCC (HCC-C), leading to chronic necro-inflammation and hepatocellular regeneration which is the background for genetic mutations to accumulate and cells to progress to overt malignancy. Nevertheless, a certain number of HCCs arise in non-cirrhotic livers (HCC-NC) that occurs in a proportion of cases ranging from 7% to 54% across the geographic areas and according to the aetiology of the liver disease (Trevisani et al., 2010). The underlying molecular mechanism for the pathophysiological differences between these two types of HCC (HCC-C and HCC-NC) is poorly understood (Tretiakova et al., 2010).
p53, is one of the well-recognized tumor suppressor genes, reported to be mutated or downregulated in many human HCC (Iakova et al., 201; Neamatallah et al., 2014).
c-Jun, is a member of the AP-1 (activator protein 1) complex that has been suggested to act as an oncogene or tumor suppressor gene which is considered a matter of debate (Eferl and Wagner, 2003; Rohr-Udilova et al., 2014).
c-Myc, encoded by proto-oncogene Myc, is a pleiotropic transcription factor that participates in the control of a wide variety of genes that are involved in the regulation of cell growth, cell proliferation, apoptosis, and differentiation by stimulating metabolism and protein synthesis. Dysregulation of Myc is commonly found in several cancers. In the liver, forced overexpression of Myc leads to spontaneous HCC (Meyer and Penn, 2008; Qu et al., 2014).
p21WAF1/CIP1 (p21), is an immediate downstream effector of p53 and acts as a broad-acting cyclin-dependent kinase (CDK) inhibitor. Upon exposed to radiation and other DNA-damaging agents, cells increase their p21 production, predominantly leading to cell cycle arrest at the G1 checkpoint, which allows time for DNA repair before S phase entry. It is frequently downregulated in cancer including HCC (Harper et al., 1993; Wu et al., 2011).
The present study aimed to investigate the differences in the expression of p53, c-Jun, c-Myc and p21 between HCC-C and HCC-NC to verify the underlying molecular pathways and to correlate their expression with the available clinical and histopathological data
The present work was carried out on 103 liver specimens from patients presented with HCC {86 HCC with cirrhosis (HCC-C) and 17 HCC without cirrhosis (HCC-NC)} including tumorous and non-tumorous tissue, 10 liver specimens from patients presented with cirrhosis without HCC and 10 liver specimens from patients presented with chronic hepatitis C. These tissue specimens were collected from the archival material of Pathology Department, National Liver Institute, Menofiya University. Histological examination was performed on tissue sections cut from the representative paraffin blocks of the studied cases and immunohistochemical staining for p53, c-Jun, c-Myc and p21 antibodies was performed on tissue sections cut from tissue microarray blocks containing the cores of the studied cases.
By statistical analysis, the present study demonstrated that HCC-C dose not differ greatly from HCC-NC in most clinical and pathological criteria except for male predominance (P=0.04) and the larger size of HCC mass (P=0.04) which were in favor of HCC-NC group.
p53, was not expressed in both cirrhosis and chronic hepatitis groups in comparison to its expression in HCC group (41%) (P=0.002), and in only 2% of the corresponding adjacent non-neoplastic liver. p53 protein expression did not differ between HCC-C (39.5%) and HCC-NC (47%) subgroups. Furthermore, positive expression of p53 was significantly associated with male gender (P=0.007).
c-Jun, was expressed in 100% of chronic hepatitis group, 11.7% of HCC group and not in cirrhosis group (P<0.001). This significant difference was also demonstrated by comparing its expression between cirrhosis and chronic hepatitis groups (P<0.001). c-Jun was expressed in 42.7% of the adjacent non neoplastic liver areas with a significant difference compared to the malignant areas in HCC group (P=0.001). c-Jun expression was associated with longer survival time in HCC group and its expression did not differ between HCC-C and HCC-NC subgroups (P=0.2).
c-Myc was expressed in 100% of both chronic hepatitis and cirrhosis groups and in 86.4% of HCC group. The intensity of staining of c-Myc assessed by H score was higher in HCC and cirrhosis groups in comparison to chronic hepatitis group (P<0.001).
c-Myc was expressed in 86.4% of HCC cases and in 83.5% of the corresponding adjacent non-neoplastic tissue with absence of statistical significant difference. However, the intensity of staining assessed by H score was significantly higher in the malignant group (mean=128.5) compared to the corresponding adjacent non-tumorous areas (mean=84.5) (P=0.001). c-Myc expression in HCC cases was highly associated with higher tumor differentiation (P=0.005) and higher values of alpha fetoprotein (P=0.04).
p21 was expressed in 50% of chronic hepatitis group and in 57.3% of HCC group compared to 100% of cirrhosis group (P=0.03). The cytoplasmic pattern of p21 expression was predominant in the studied groups while nuclear expression was only seen in 5 cases of HCC and 2 cases of chronic hepatitis groups (P=0.04). Survival time was positively correlated with H score values of p21 expression in the HCC group (P=0.03).
H-score values of p21 expression showed higher median values in HCC-C (median=50) compared to HCC-NC (median=20) (P=0.03) and this is the only difference that have been found by comparing the expression of the studied markers (p53, c-Jun, c-Myc and p21) between HCC-C and HCC-NC groups.
Studying the relationships between the studied markers, p21 expression was significantly associated with higher median and mean values of H score of c-Myc expression (P=0.01) and cytoplasmic p21 expression was associated with higher median and mean values of H score of p53 expression (P=0.03).
None of the studied clinicopathological parameters in HCC and immunohistochemical markers (p53, c-Jun, c-Myc and p21) proved to have any impact on patient outcome using Log Rank equation.
HCC cases arising from the left lobe (P=0.07), positive cases for p21 expression (P=0.09) and nucleocytoplasmic c-Myc expression (P=0.09) tended to show more liability for recurrence in comparison to cases arising in right lobe, negative p21 expression and cytoplasmic pattern of c-Myc expression, respectively. However, these associations were near significant. By multivariate analysis, none of the above parameters showed independent significant value.