Frequency and features of TP53 mutation in 30 Chinese patients with sporadic basal cell carcinoma.

ABSTRACT

BACKGROUND: Basal cell carcinoma (BCC) is a prevalent form of nonmelanoma skin cancer. Although numerous studies in white populations suggest that mutations in the TP53 gene play an important role in the development of BCC, it is not clear whether this is also the case in East Asian populations such as in China. AIM: To investigate the frequency and the features of TP53 mutation in sporadic BCC in a Chinese population. METHODS: In total, 30 patients with sporadic BCC, who had previously taken part in a study on PTCH1 mutations, were enrolled. BCC and control cells were obtained by laser-capture microdissection, and DNA was amplified and sequenced for analysis of TP53 mutations. RESULTS: In the 30 BCC samples, 6 TP53 point mutations were found (frequency of 20%), and 4 of these 6 mutations had ultraviolet (UV)-specific alterations. Combining these results with those of the previous study on PTCH1 mutations, we found that two patients with had three types of genetic alterations (each had two PTCH1 mutations and one TP53 point mutation). A further two patients each had one PTCH1 mutation and one UV signature TP53 mutation. In addition, the total number of UV-specific mutations of PTCH1 and TP53 accounted for 20% of the total patient group. CONCLUSIONS: The incidence of TP53 mutation in BCC in our Chinese subjects was lower than that reported for white populations. Many of the patients carried mutations of other genes in addition to of TP53. The majority of TP53 mutations were UV-induced specific alterations. However, the results of the two studies on TP53 and PTCH1 indicated that the incidence of UV-specific mutations is much lower in Chinese than in white populations.