Is the p53 inactivation frequency in squamous cell carcinomas of the head and neck underestimated? Analysis of p53 exons 2-11 and human papillomavirus 16/18 E6 transcripts in 123 unselected tumor specimens - Balz, V; Scheckenbach, K; Götte, K; Bockmühl, U; Petersen, I; Bier, H (Cancer Res, 2003)