KRAS and adenocarcinoma: In addition, molecular studies in humans ‘further suggest that asbestos enhances the mutagenicity of tobacco carcinogens and that it acts, at least in part, independent of the tissue damage responsible for fibrosis.’ [87] Nelson et al. [65] investigated k-ras codon 12 mutations among 84 male patients with adenocarcinoma of lung for whom a work history was available, as well as a chest radiograph for all those who had a history of occupational exposure to asbestos.