Replication protein A (RPA), a component of the origin recognition complex, is required for stabilization of single-stranded DNA at early and later stages of DNA replication being thus critical for eukaryotic DNA replication. Experimental studies in colon cancer cell lines have shown that RPA protein may be the target of cytotoxins designed to inhibit cellular proliferation. This is the first study to investigate the expression of RPA1 and RPA2 subunits of RPA protein and assess their prognostic value in colon cancer patients. We analyzed immunohistochemically the expression of RPA1 and RPA2 proteins in a series of 130 colon cancer resection specimens in relation to conventional clinicopathological parameters and patients' survival. Statistical significant positive associations emerged between: (a) RPA1 and RPA2 protein expressions (P ¼ 0.0001), (b) RPA1 and RPA2 labelling indices (LIs) and advanced stage of the disease (P ¼ 0.001 and 0.003, respectively), (c) RPA1 and RPA2 LIs and the presence of lymph node metastasis (P ¼ 0.002 and 0.004, respectively), (d) RPA1 LI and the number of infiltrated lymph nodes (P ¼ 0.021), (e) RPA2 LI and histological grade of carcinomas (P ¼ 0.05). Moreover, a statistical significant higher RPA1 LI was observed in the metastatic sites compared to the original ones (P ¼ 0.012). RPA1 and RPA2 protein expression associated with adverse patients' outcome in both univariate (log rank test: Po0.00001 and 0.00001, respectively) and multivariate (Cox model: P ¼ 0.092 and 0.0001, respectively) statistical analysis. Statistical significant differences according to the expression of RPA1 and RPA2 proteins were also noticed in the survival of stage II (Po0.00001 and 0.0016, respectively) and stage III (P ¼ 0.0029 and 0.0079, respectively) patients. In conclusion, RPA1 and RPA2 proteins appear to be useful prognostic indicators in colon cancer patients and attractive therapeutic targets for regulation by tumor suppressors or other proteins involved in the control of cell proliferation. Modern Pathology (2007) 20, 159-166.

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Minichromosome maintenance proteins (MCM) have recently emerged as novel proliferation markers with prognostic implications in several tumour types. This is the first study investigating MCM-2 and MCM-5 immunohistochemical expression in a series of ovarian adenocarcinomas and low malignant potential (LMP) tumours aiming to determine possible associations with clinicopathological parameters, the conventional proliferation index Ki-67, cell cycle regulators (p53, p27 Kip1 , p21 WAF1 and pRb) and patients' outcome. Immunohistochemistry was applied in a series of 43 cases of ovarian LMP tumours and 85 cases of adenocarcinomas. Survival analysis was restricted to adenocarcinomas. The median MCM-2 and MCM-5 labelling indices (LIs) were significantly higher in adenocarcinomas compared to LMP tumours (Po0.0001 for both associations). In adenocarcinomas, the levels of MCM-2 and MCM-5 increased significantly with advancing tumour stage (P ¼ 0.0052 and P ¼ 0.0180, respectively), whereas both MCM-2 and MCM-5 increased significantly with increasing tumour grade (P ¼ 0.0002 and P ¼ 0.0006, respectively) and the presence of bulky residual disease (Po0.0001 in both relationships). A strong positive correlation was established between MCM-2 or MCM-5 expression level and Ki-67 LI (Po0.0001) as well as p53 protein (P ¼ 0.0038 and P ¼ 0.0500, respectively). Moreover, MCM-2 LI was inversely correlated with p27KipÀ1 LI (P ¼ 0.0068). Finally, both MCM-2 and MCM-5 were associated significantly with adverse patients' outcome in both univariate (X20 vs 420%, P ¼ 0.0011 and X25 vs o25%, P ¼ 0.0100, respectively) and multivariate (P ¼ 0.0001 and 0.0090, respectively) analysis. An adequately powered independent group of 45 patients was used in order to validate our results in univariate survival analysis. In this group, MCM-2 and MCM-5 expression retained their prognostic significance (Po0.0001 in both relationships). In conclusion, MCM-2 and MCM-5 proteins appear to be promising as prognostic markers in patients with ovarian adenocarcinomas.

Caspase-3 is the ultimate executioner caspase that is essential for the nuclear changes associated with apoptosis. We investigated caspase-3 immunohistochemical expression in 58 primary intracranial meningiomas, using one monoclonal antibody detecting both precursor and cleaved caspase-3 (CPP32) and a second recognizing only the cleaved activated form (ASP175). Caspase-3 expression was analyzed in relation to baseline apoptosis-as illustrated by the expression of anti-single stranded DNA (ss-DNA), the antiapoptotic protein bcl-2, proliferation indices (Ki-67, PCNA, topoisomerase IIa, mitosin C), hormonal status (estrogen, progesterone, androgen receptors), standard clinicopathological parameters and patients' disease-free survival. Caspase-3 immunostaining was observed in 62% of cases for CPP32 and in 24% for ASP175. In both instances, the labeling index (LI) was significantly correlated with ss-DNA LI (p=0.038 and p=0.018). CPP32 but not ASP175 LI positively correlated with the mitotic index (p=0.001) and PCNA LI (p=0.004). Both CPP32 and ASP175 LIs were increased in nonbenign meningiomas (p<0.0001 and p=0.0035 respectively). In univariate and multivariate survival analyses, caspase-3 predicted meningioma recurrence, independently affecting disease-free survival (p=0.011 and p=0.047 respectively for CPP32; p<0.0001 and p=0.012 respectively for ASP175). Caspase-3 may prove to be a useful predictor of early recurrence in a group of neoplasms characterized by the frequent discordance between histology and clinical behavior.

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