ERK/pERK expression and B-raf mutations in colon adenocarcinomas: correlation with clinicopathological characteristics.

BACKGROUND: Colorectal (CRC) carcinogenesis through various morphological stages has been linked to several genetic and epigenetic changes. The Raf/MEK/ERK (MAPK) signal transduction cascade is an important mediator of a number of cellular fates. METHODS: In this study, we investigated the presence of B-raf and K-ras mutations in 94 consecutive cases of primary colon adenocarcinoma in correlation with the immunohistochemical expression of total and activated ERK and the expression of mismatch repair proteins (MMR) hMLH1 and hMSH2 as well as their correlations with standard clinicopathological parameters. RESULTS: The immunostaining pattern for total and activated ERK was nuclear and cytoplasmic. hMLH1 and hMSH2 proteins were preserved in 45/63 (71.43%) cases and 35/53 (66.04%) cases respectively. Total ERK nuclear expression, was positively correlated with tumor stage (p = 0.049), whereas nuclear pERK expression was positively correlated with histological grade (p = 0.0113) and tumor stage (p = 0.0952), although the latter relationship was of marginal significance. DNA sequencing showed that 12 samples (12.7%) had a mutation in B-RAF Exon 15 and none in Exon 11, whereas 22 (23.4%) had a K-ras mutation. Disruption of the MAP kinase pathway-either through K-ras or B-raf mutation-was detected in 37% of all the examined cases, although the overexpression of total and activated ERK1/2 was not correlated with the mutational status of K-ras or B-raf genes. Finally, the preservation of hMLH1 or hMSH2 immunoexpression was not correlated with the presence of B-raf and/or K-ras mutations. CONCLUSIONS: In this study, we present evidence that ERK activation occurs in a K-ras or B-raf -independent manner in the majority of primary colon cancer cases. Moreover, B-raf mutations are not associated with mismatch-repair deficiency through loss of hMLH1 or hMSH2 expression. Activated ERK could possibly be implicated in tumor invasiveness as well as in the acquisition of a more aggressive phenotype.

Clinical significance of nuclear factor (NF)-kappaB levels in urothelial carcinoma of the urinary bladder.

Nuclear factor (NF)-kappaB has been reported to be constitutively activated in various human neoplasms. However, its clinical significance in bladder urothelial carcinoma (UC) remains an unresolved issue. We conducted this study trying to elucidate the role of NFkappaB in bladder UC and its potential prognostic significance, by quantifying immunohistochemically the levels of p65/RelA expression in paraffin-embedded tissue from 116 patients. Some of the cases had previously been stained for cellular FLICE-like inhibitory protein (c-FLIP) and bcl-2. Seventy-four cases displayed concurrent cytoplasmic and nuclear immunoreactivity, whereas 18 only nuclear immunoexpression and 21 only cytoplasmic immunoexpression, and the remaining three cases were negative for p65/RelA. Nuclear p65/RelA expression was positively associated with tumour grade and T-category (p=0.0001 in both cases). In addition, cytoplasmic p65/RelA expression was lower in advanced T-category (p=0.0030). Moreover, p65/RelA nuclear expression was positively correlated with c-FLIP (p=0.0109) and bcl-2 (p=0.0452). p65/RelA nuclear expression adversely affected survival in both univariate and multivariate analysis in superficial (Ta-T1; p=0.0010 and p=0.0008) as well as in muscle-invasive carcinomas (T2-T4; p=0.0004 and p=0.0003). Our results demonstrate that NF-kappaB nuclear expression is correlated with histologic grade and T category in bladder UC. Moreover, NF-kappaB nuclear expression emerges as an independent prognosticator of adverse significance, conveying information beyond that obtained by standard clinicopathological prognosticators.

TRAIL and osteoprotegerin (OPG) expression in bladder urothelial carcinoma: correlation with clinicopathological parameters and prognosis.

AIMS: To investigate the expression of tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and osteoprotegerin (OPG) in bladder urothelial carcinomas (UCs) and assess possible interrelations with other regulators of TRAIL induced apoptosis (p65/NF-κB, p-ERK1/2, p-AKT) and FGFR3, as well as to elucidate their potential involvement in bladder tumourigenesis and determine their potential prognostic utility. METHODS: Paraffin embedded transurethral resection tissue from 128 patients with UC was immunostained for TRAIL and OPG as well as for p65/NF-κB, p-ERK1/2, p-AKT and FGFR3. RESULTS: TRAIL and OPG were coexpressed in 96.6% of cases and positively interrelated. OPG expression was significantly different among histological grades, being higher in low-grade UCs and was inversely correlated with the presence of lymphovascular invasion (LVI). TRAIL also displayed an inverse relationship with histological grade, T-category and LVI. Both OPG and TRAIL expression were positively correlated with FGFR3 expression, the former relationship being marginal. Moreover, increased TRAIL expression was marginally correlated with lower NF-κB/p65 nuclear expression. Increased OPG expression adversely affected survival both in univariate and multivariate analysis. CONCLUSIONS: OPG and TRAIL are frequently expressed and coexpressed in UCs, supporting the involvement of OPG in the resistance to TRAIL-driven apoptosis. Inhibition of NF-κB activation may also play a similar role, although less important. OPG emerged as an independent prognostic marker of adverse significance.

Analysis of PRNP gene codon 129 polymorphism in the Greek population.

Creutzfeldt-Jakob disease (CJD) is a fatal transmissible neurodegenerative prion disease with a rapid progression comprising familial, sporadic, iatrogenic and variant forms. A polymorphism at codon 129 of PRNP gene has been implicated in the development of variant CJD. We examined Met/Val allele frequencies and the genotype distribution, with respect to the polymorphic codon 129 of PRNP gene in 348 healthy individuals from the region of Athens, Greece. The following genotype frequencies were observed in the Greek population: Met/Met 50%, Met/Val 39% and Val/Val 11%. The presence of the Methionine allele frequencies in various European populations, according to the published data, increases gradually from northwestern to southeastern countries, implying the presence of a cline. The distribution of genotypes of Met homozygotes displays random declination across the 10 compared populations. The observed higher frequency of Met homozygotes at codon 129 does not necessarily suggest that these populations are at increased risk of developing CJD.