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Mutations of the p53 gene in nasal NK/T-cell lymphoma
1Department of Pathology, Osaka University Medical School, Japan.
Abstract:
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.
Insights
p53 gene mutations and abnormal protein expression were investigated in nasal NK/T-cell lymphoma. Researchers found mutations in 47.6% of patients, suggesting potential links to environmental or lifestyle factors.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- p53 tumor suppressor gene mutations are common in many cancers, including lymphomas.
- p53 gene mutations in nasal NK/T-cell lymphoma remain understudied due to tissue limitations.
Purpose of the Study:
- To investigate the frequency and types of p53 gene mutations and protein expression in nasal NK/T-cell lymphoma.
- To explore potential correlations between p53 alterations and geographical or demographic factors.
Main Methods:
- Analysis of paraffin-embedded nasal tumor specimens from 42 Chinese and Japanese patients.
- Utilized immunohistochemistry for p53 protein expression and single-strand conformation polymorphism (SSCP) with PCR for gene mutation analysis, followed by direct sequencing.
Main Results:
- p53 gene mutations were detected in 47.6% (20/42) of cases, with 18 missense, 9 silent, and 1 nonsense mutation identified.
- Abnormal p53 protein expression was observed in 45.2% (19/42) of patients.
- A significantly higher incidence of abnormal p53 expression (4-fold) was noted in Osaka cases, despite lower mutation rates compared to other regions.
Conclusions:
- p53 gene alterations are frequent in nasal NK/T-cell lymphoma.
- Geographical variations in p53 expression suggest potential influences of racial, environmental, or lifestyle factors on tumorigenesis.