Ras mutation cooperates with β-catenin activation to drive bladder tumourigenesis

Mutations in the Ras family of proteins (predominantly in H-Ras) occur in approximately 40% of urothelial cell carcinoma (UCC). However, relatively little is known about subsequent mutations/pathway alterations that allow tumour progression. Indeed, expressing mutant H-Ras within the mouse bladder does not lead to tumour formation, unless this is expressed at high levels. The Wnt signalling pathway is deregulated in approximately 25% of UCC, so we examined if this correlated with the activation of MAPK signalling in human UCC and found a significant correlation. To test the functional significance of this association we examined the impact of combining Ras mutation (H-RasQ61L or K-RasG12D) with an activating β-catenin mutation within the mouse bladder using Cre-LoxP technology. Although alone, neither Ras mutation nor β-catenin activation led to UCC (within 12 months), mice carrying both mutations rapidly developed UCC. Mechanistically this was associated with reduced levels of p21 with dependence on the MAPK signalling pathway. Moreover, tumours from these mice were sensitive to MEK inhibition. Importantly, in human UCC there was a negative correlation between levels of p-ERK and p21 suggesting that p21 accumulation may block tumour progression following Ras mutation. Taken together these data definitively show Ras pathway activation strongly cooperates with Wnt signalling to drive UCC in vivo

Geographic variations of human papilloma virus infection and their possible impact on the effectiveness of the vaccination programme

Greece is one of the first countries of the European Union to introduce a human. papilloma virus (HPV) vaccine in its national vaccination programme. Geographical variations in the prevalence of the different HPV types have been demonstrated. The aim of this preliminary case control study was to investigate HPV infection in women with low- and high-grade squamous intraepithelial lesions (SILs) from two different geographical areas of Greece; Central Greece and Crete. Seventy-five cervical specimens were collected from women with SILs from Crete and Central Greece. HPV detection and typing were performed by using polymerase chain reaction (PCR) techniques. HPV-18 was detected more frequently in Crete than in the Central Greece samples (29.7 vs 13.1%). HPV-16 was predominant in Central Greece (34.2%), while in Crete it was detected in 23% of the studied women. Non-16/-18 HPV types were detected in 45.9% of the women from Crete and 52.6% of the women from Central Greece. No relationship was observed between the geographical distribution of HPV and the presence of K-ras or B-raf point mutations in either group. Our pre-vaccination data indicate a high prevalence of HPV-18 in Crete. A trend for difference was observed in the rates of non-HPV-16/-18 women between the two areas. A large epidemiological study is required to investigate the prevalence of the different HPV types to further investigate the effectiveness of HPV vaccination in the Greek population

Mismatch DNA repair mRNA expression profiles in oral melanin pigmentation lesion and hamartomatous polyp of a child with peutz-jeghers syndrome

Mismatch DNA repair (MMR) mRNA expression analysis was performed on a biopsy of oral mucosa melanin pigmentation lesion, a hamartomatous polyp and peripheral blood derived from a 12-year-old child with Peutz-Jeghers Syndrome (PJS). We present a deficient MMR system, in a PJS patient, which demonstrated low mRNA levels of hMSH6 and hPMS2 and an increasing MMR deficiency from the non-dysplastic lesion to hamartomatous polyp of PJS with a high risk of cancer. Pediatr Blood Cancer 2013;60:E116-E117. (c) 2013 Wiley Periodicals, Inc

High-risk human papillomavirus (HPV) in parotid lesions

Although several studies have reported that oropharyngeal infection with HPV may predispose to tumorigenesis, little is known about the etiological factors of salivary gland tumors and the presence of HPV. We studied 9 parotid lesions for HPV infection including an oncocytoma, an acinic cell carcinoma, a high-grade adenocarcinoma, a low-grade polymorphous adenocarcinoma, a Warthin's tumor and 2 pleomorphic adenomas, a lymphoepithelial cyst and a lipoma of the parotid gland. DNA was extracted from formalin-fixed and paraffin-embedded tissue sections. Solution PCR for HPV detection was performed using the GP5+/GP6+ primers, while HPV typing was carried out by multiplex PCR for HPV6, 11, 16, 18, and 33; positive samples were recorfirmed by PCR with specific primers for each type. Quantitative real-time PCR for the high-risk HPV genotypes 16, 18, 31, 33, 35, 52, 58 and 67 was also performed to quantitate the viral load. Finally, in situ PCR was employed with HPV16-specific primers by direct-detection method. Seven of the 9 parotid lesions were HPV positive while 6 of these 7 had been infected by HPV16 and/or HPV18 oncogenic types. High viral load of high-risk genotypes of HPV was found in the oncocytoma, in one of the pleomorphic adenomas, and in the Warthin's tumor. Finally, in situ PCR indicated that HPV16 amplification occurred in the salivary gland tumors. This is the first time that high-risk HPV genotypes are detected in these histological types of parotid lesions, suggesting the possible involvement of the virus in the disease

Genomic Instability and Loh at 2 Polymorphic Sites in the H-Ras1 Gene

Journal URL: http://www.spandidos-publications.com/ijo

Microsatellite instability and loss of heterozygosity at the MEN1 locus in lung carcinoid tumors: A novel approach using real-time PCR with melting curve analysis in histopathologic material

The possible causes and genetic mechanisms of pulmonary carcinoid tumor development are unclear. In this study, we examined genetic alterations at the MEN1 locus in archival material from 15 pulmonary carcinoids. We employed, for the first time in this setting, real-time PCR with melting curve analysis in order to identify loss of heterozygosity (LOH) or microsatellite instability (MI) in two polymorphic markers (PYGM, D11S449) at the MEN1 locus and one additional marker (D11S906) of a putative oncosuppressive region distal to the MEN1 gene. Sequencing data were available in a selected subset of tumors in order to verify the reliability of real-time PCR analysis. We observed LOH at PYGM in 38% of the cases and MI in 13.3% of the cases. Our data indicate that real-time PCR with melting curve analysis is a reliable technique for LOH and MI detection and indicate that genetic errors at the MEN1 locus but also distal to it may be involved in the development of sporadic pulmonary carcinoid tumors