TP53 mutations in prostatic cancer. Analysis of pre‐ and post‐treatment archival formalin‐fixed tumour tissue

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Abstract
The TP53 gene mutation pattern in prostatic cancer was examined in relation to progression and survival, using archival formalin‐fixed pre‐and post‐treatment tumour specimens from 84 prostatic cancer patients. Thirty‐four had hormone‐sensitive tumours and 50 were hormone‐resistant. Six of the 34 (18 per cent) therapy‐responding tumours and 19 of the 50 (38 per cent) hormone‐resistant tumours showed p53 protein accumulation in the post‐treatment specimen. Both pre‐ and post‐treatment specimens from these 25 patients were analysed for mutation of the conserved regions of the TP53 gene (exons 5–8), using constant denaturant gel electrophoresis (CDGE) followed by DNA sequencing. In the post‐treatment samples, mutations were detected in three of the six patients with hormone‐responsive tumours and in 11 of the 19 patients with hormone‐resistant tumours. The three (100 per cent) patients with therapy‐responsive tumours with mutations and nine of the 11 (82 per cent) patients with therapy‐resistant tumours with mutations died of the disease. Thirteen of the 14 mutations in the post‐treatment specimens were transitions, 11 occurring at CpG dinucleotides in which codon 273 was involved in ten. A significantly higher proportion of tumours with mutations were poorly differentiated compared with tumours without mutation (P<0·04). Our findings indicate that TP53 mutation is a late event in tumour development of the prostate gland and that codon 273 might be a ‘hotspot’ for mutation in the progression of the disease.