K-ras mutations in 239PuO2 canine lung neoplasms.

Area of Science:

• Radiobiology
• Oncology
• Molecular Biology

Background:

• Plutonium dioxide (239PuO2) inhalation exposure is a known risk factor for lung cancer.
• Investigating genetic alterations in lung tumors can elucidate cancer development mechanisms.

Purpose of the Study:

• To identify mutations in the K-ras gene in lung tumors from beagle dogs exposed to 239PuO2.
• To compare the frequency of K-ras mutations in plutonium-induced lung tumors to other canine and human lung cancers.

Main Methods:

• Single-strand conformational polymorphism (SSCP) analysis and direct sequencing were employed.
• Tumor tissues from 25 beagle dogs with documented 239PuO2 inhalation exposure and subsequent lung tumors were analyzed.
• Exon 1 of the K-ras gene was specifically examined for mutations.

Main Results:

• Mutations in the K-ras gene were detected in 2 out of 25 (8%) plutonium-induced lung tumors.
• Both identified mutations were GGT to GAT transitions at codon 12.
• The mutation rate (8%) was higher than in previous studies of canine plutonium-induced lung tumors (0%) but lower than in spontaneous canine lung cancer (16%) and human non-small cell lung cancer (13-36%).

Conclusions:

• The K-ras gene is a potential target for mutations in plutonium-induced canine lung cancer.
• The observed mutation frequency suggests a role for K-ras in the pathogenesis of radiation-induced lung tumors.
• Further research is warranted to understand the full spectrum of genetic changes in plutonium-induced lung cancers.