Mutations of the p53 gene in nasal NK/T-cell lymphoma.
Mutations of the p53 tumor suppressor gene are reported in various kinds of malignancies including lymphomas. However, p53 gene mutations in nasal NK/T-cell lymphoma have not been reported because most parts of tumors are necrotic and a small amount of living tumor tissues is available for the molecular study. Expression and mutations of the p53 gene were examined in the paraffin-embedded specimens of the nasal lesions from 42 Chinese (Beijing and Chengdu) and Japanese (Okinawa and Osaka) patients with nasal NK/T-cell lymphoma by the immunohistochemistry and single strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) amplified products followed by direct sequencing. Thirty single-nucleotide substitution mutations were observed in 20 of 42 cases (47.6%). Among the 30 mutations, 18 were missense (mainly G:C to A:T transitions), 9 were silent, and 1 was a nonsense mutation. The remaining 2 mutations involved intron 5 and exon 5 terminal points. Abnormal expression of the p53 protein was also observed in 19 of 42 (45.2%) cases. The incidence was significantly (4-fold) higher in the cases of Osaka than those in other areas, although the incidence of p53 mutations in the cases of Osaka was one-half to one-third of those in the other three areas. The results may suggest some racial, environmental, or lifestyle differences in the cause of nasal tumorigenesis.
Li
T
T
Department of Pathology, Osaka University Medical School, Japan.
Hongyo
T
T
Syaifudin
M
M
Nomura
T
T
Dong
Z
Z
Shingu
N
N
Kojya
S
S
Nakatsuka
S
S
Aozasa
K
K
D000328:Adult; D000368:Aged; D005260:Female; D016158:Genes, p53; D006801:Humans; D007694:Killer Cells, Natural / Q000473:pathology; D016399:Lymphoma, T-Cell / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology