Reduced expression of connexin 31.1 in larynx cancer is not caused by GJB5 mutations.

Lack of regular cell-cell interaction is one major cause for neoplastic growth and metastasis. In head and neck squamous cell carcinomas a 10-fold down-regulation of connexin31.1 (GJB5) as well as mutations in the TGF-beta-receptor-II were reported. We performed mutation screenings in GJB5 and the TGF-beta-receptor-II poly(10)adenine hot spot employing larynx cancer samples of 10 patients. Variable length of the TGF-beta-receptor-II adenine homopolymer in controls and tumours indicate a high slippage error rate of the DNA polymerases rendering mutational analyses inconsistent. Lack of GJB5 mutations in the entire tumour collection suggests that this gene is not primarily involved in laryngeal tumorigenesis.