[p53 mutations/p53 protein overexpression. Differential significance for the progression of head-neck carcinomas]

P53 mutation is a rare event in Merkel cell carcinoma of the head and neck

The aim of this retrospective analysis was to evaluate the status of p53 and possible mutations in Merkel cell carcinoma (MCC) cell lines and MCC tissue samples. The p53 mutations are common in different cancer origins but rare in MCCs detected so far. MCCs are highly aggressive neuroendocrine tumors with an enhanced potential to metastasize. Until now, less is known about MCC and new approaches to understand this disease are necessary. RNA and DNA were extracted from two MCC cell lines and 27 archival paraffin-embedded patient samples. After reverse transcription, a real-time PCR and a high-resolution melt analysis were carried out. In both MCC cell lines, we could detect a p53 missense mutation at codon 193 (exon 6) with a change in amino acids (His → Leu). This mutation was equal in both cell lines and was investigated in 27 tissue samples in succession to detect possible accounts for the aggressive behavior of MCCs. Unfortunately, no corresponding p53 mutation could be observed in the investigated tissue samples. A new p53 mutation was detected in MCC cell lines. This mutation could not be determined in patients' samples. Therefore, the aggressiveness of MCC seems to be independent of p53 mutations and other mutations might be responsible for developing MCC.