B-Raf Mutations, Microsatellite Instability and p53 Protein Expression in Sporadic Basal Cell Carcinomas

Abstract

Basal Cell Carcinoma (BCC) is the most common skin malignancy. Genes related to the Ras/Raf signalling pathway have been implicated in the pathogenesis of skin cancer. The objective of this study was to investigate the presence of B-Raf mutations in sporadic BCCs as well as its correlation with the phenotype of microsatellite instability (MSI), the clinicopathological parameters of the tumours and p53 protein expression. 83 BCC specimens were screened for B-Raf mutations, applying polymerase chain reaction, single-stranded conformation polymorphism (PCR-SSCP) and DNA sequencing. MSI status was examined using mononucleotide microsatellite markers and p53 protein expression was demonstrated by immunohistochemical staining. A C to T transition at 1790 nucleotide leading to a silent mutation L597L; and a T to A transversion causing an amino acid change (F610I) have been found. MSI was detected in 5% of the cases and p53 accumulation was present in 37/83 samples studied. Although rare B-Raf alterations have been observed in BCC, none of them harboured the hot-spot mutation T1799A commonly present in melanomas and colon carcinomas. Consequently, no correlation could be determined between B-Raf alterations, MSI status, the clinicopathological features and p53 protein expression. Our results are in favour of a secondary importance for Ras signalling cascade genes in BCC pathogenesis.

TERTp mutations and p53 expression in head and neck cutaneous basal cell carcinomas with different aggressive features

“…In our study, most cBCCs overexpressed the p53 protein (60.5%), a frequency higher than the 45% found by Stamatelli et al 23 but similar to the values observed by Haghighi et al 24 ; both authors used the ≥ 10% cut-off to consider p53 positive expression. No associations were found between p53 overexpression and the clinical and histological features of the cBCCs, except for necrosis.…”

“…The scoring of tumors was done as follows: staining < 10% of tumor cells were considered as negative, and staining ≥ 10% was considered as positive 23 , 24 .…”

BRAF V600E and Novel Somatic Mutations in Thyroid Cancer of Libyan Patients

“…The L597L (c.1791 A>T) mutation was found in a 47-year women with papillart thyroide carcinoma. This mutation was reported previously in one over 83 Basal cell carcinomas of the skin (Stamatelli et al, 2011) and it was considered as pathogenic in COSMIC (score 0.95)…”