Looking for Causation by Seeking Patterns in Somatic Mutations in Tumors
Researchers continue to seek out “fingerprint” patterns in tumor mutation patterns in order to look back towards causation and source of disease. A recent study in France looked at somatic mutation patterns in lung cancers in never smokers who may have been exposed to “passive” tobacco smoke. See No impact of passive smoke on the somatic profile of lung cancers in never-smokers, published online before print March 5, 2015, doi:10.1183/09031936.00097314ERJ March 5, 2015 ERJ-00973-201 (2014).
The abstract states:
EGFR and HER2 mutations and ALK rearrangement are known to be related to lung cancer in never-smokers, while KRAS, BRAF andPIK3CA mutations are typically observed among smokers. There is still debate surrounding whether never-smokers exposed to passive smoke exhibit a “smoker-like” somatic profile compared with unexposed never-smokers.
Passive smoke exposure was assessed in the French BioCAST/IFCT-1002 never-smoker lung cancer cohort and routine molecular profiles analyses were compiled.
Of the 384 patients recruited into BioCAST, 319 were tested for at least one biomarker and provided data relating to passive smoking. Overall, 219 (66%) reported having been exposed to passive smoking. No significant difference was observed between mutation frequency and passive smoke exposure (EGFR mutation: 46% in never exposed versus 41% in ever exposed; KRAS: 7%versus 7%; ALK: 13% versus 11%; HER2: 4% versus 5%; BRAF: 6%versus 5%; PIK3CA: 4% versus 2%). We observed a nonsignificant trend for a negative association between EGFR mutation and cumulative duration of passive smoke exposure. No association was found for other biomarkers.
There is no clear association between passive smoke exposure and somatic profile in lifelong, never-smoker lung cancer.”