High K-ras mutation rates in goblet-cell-type adenocarcinomas of the lungs

Adenocarcinomas of the lungs show a variable histology. We have subclassified such lesions into five cell types: hobnail, columnar, polygonal, mixed and goblet cell types, and investigated their relationships with K-ras mutations. Codons 12, 13 and 61 of the K-ras gene in 120 surgically resected pulmonary adenocarcinomas were examined by the mutation-allele-specific amplification method. Point mutations were observed in 10% of the adenocarcinomas limited to K-ras codon 12 and the commonest base substitution (nine cases) was a G to T transversion. Of the five types, goblet cell lesions demonstrated the highest mutation index, which at 100% (6/6) was significantly different from that of all other cell types. No relationship between K-ras mutation and cigarette smoking was observed. From these findings, it appears that development of goblet-cell-type adenocarcinomas of the lung may involve different carcinogenic mechanisms from adenocarcinomas of other subtypes.