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Abstract: The susceptibility to hepatocellular carcinoma (HCC) varies greatly within human populations in response to environmental risk agents. The mechanisms underlying differential susceptibility are still largely unknown and need to be clarified to improve HCC chemoprevention and therapeutic treatment. Inbred rodent strains with established predispositions for hepatocarcinogenesis offer the opportunity to identify intrinsic susceptibility and resistance factors. Previously, we have characterized mouse strains showing differential susceptibility to o-aminoazotoluene (OAT) and established that susceptibility does not result from OAT metabolism or genotoxicity in the livers of resistant and susceptible mice. In this study we have found that OAT differently affects hepatocyte proliferation in mice after partial hepatectomy (PH). OAT inhibited hepatocyte proliferation by 60–80% in the livers of susceptible mice, whereas resistant mice showed less than 15% inhibition. The inhibition resulted in significant delay of hepatic mass recovery in susceptible mice. OAT induced p53 stabilization and transcriptional activation in response to carcinogen treatment to the same degree in both, susceptible and resistant mice. Taken together, our data support inhibition of hepatocyte proliferation as a major cause for increased mouse susceptibility to hepatocarcinogenesis, and acceleration of functional liver recovery may offer a way to increase resistance to hepatic neoplasms. These results may have relevance to clinical observations of HCCs and implications for HCC chemoprevention and treatment. [Copyright &y& Elsevier]

Abstract: We have discovered several protein biomarkers that are altered during carcinogenesis of the human uterine endometrium. Proteins prepared from 19 endometrial carcinomas (Group A), and 20 normal endometria obtained from benign gynecological conditions (Group B), were investigated by Surface Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SELDI-TOF-MS). Two proteins, EC1 and EC2, were consistently expressed differentially. EC1 had an increased level of expression in carcinomas (P<0.001), while EC2 was expressed at a lower level (P=0.004). The isoelectric points of EC1 and EC2 were approximately pH 5.0 and 7.0, respectively. These proteins are thus potential biomarkers for detection of endometrial carcinoma. [Copyright &y& Elsevier]

The CDKN2A locus on human chromosome 9p21 encodes two tumor suppressors, p14ARF and p16INK4A, which enhance the growth-suppressive functions of the retinoblastoma (Rb) and the p53 proteins, respectively. Conversely, the E6 and E7 oncoproteins of the high-risk human papillomaviruses (HPVs) causally associated with carcinogenesis of the uterine cervix contributes to tumor development by inactivating p53 and Rb. Nevertheless, a correlation between expression of p14ARF/p16INK4A and HPV infection in uterine cervix is less clear. To clarify this, we examined 25 cervical cancers and 11 normal uterine cervixes. HPV was detected in 21 of 25 cervical cancers (84%) and their subtype was determined by PCR-RFLP. Quantitative real-time RT-PCR assays showed overexpression of p14ARF mRNA in all 21 HPV-positive cases (100%). p16INK4A mRNA was overexpressed in 17 cases of the HPV-positive cases (81%). In four HPV-negative cancers, reduced expression of p14ARF mRNA was detected in two cases (50%) and reduced p16INK4A mRNA in three cases (75%). Our data indicate that the overexpression of p14ARF and p16INK4A strongly associates with HPV-positive cervical cancers and that reduced expression of p14ARF and p16INK4A correlates with HPV-negative cervical cancers. These findings may indicate that impaired p14ARF and p16INK4A mRNA expression contribute to tumor development in HPV-negative cervical cancers by failure to support p53 and Rb instead of their inactivation by HPV E6 and E7. [Copyright &y& Elsevier]