More Progress on Pinpointing Lung Cancers Caused by Smoking

Although researchers generally are not interested in litigation, their insights continue to have implications for toxic tort litigation. For example, a recent paper in Oncogene reports on Mayo researchers identifying a mutation biomarker related to one form of lung cancer in smokers. Mayo’s press release is here. The abstract for the paper states the following regarding the observed mutation:

"ASCL1 is an important regulatory transcription factor in pulmonary neuroendocrine (NE) cell development, but its value as a biomarker of NE differentiation in lung adenocarcinoma (AD) and as a potential prognostic biomarker remains unclear. We examined ASCL1 expression in lung cancer samples of varied histologic subtype, clinical outcome and smoking status and compared with expression of traditional NE markers. ASCL1 mRNA expression was found almost exclusively in smokers with AD, in contrast to non-smokers and other lung cancer subtypes. ASCL1 protein expression by immunohistochemical (IHC) analysis correlated best with synaptophysin compared with chromogranin and CD56/NCAM. Analysis of a compendium of 367 microarray-based gene expression profiles in stage I lung adenocarcinomas identified significantly higher expression levels of the RET oncogene in ASCL1-positive tumors (ASCL1+) compared with ASCL1− tumors (q-value <10−9). High levels of RET expression in ASCL1+ but not in ASCL1- tumors was associated with significantly shorter overall survival (OS) in stage 1 (P=0.007) and in all AD (P=0.037). RET protein expression by IHC had an association with OS in the context of ASCL1 expression. In silico gene set analysis and in vitro experiments by ASCL1 shRNA in AD cells with high endogenous expression of ASCL1 and RET implicated ASCL1 as a potential upstream regulator of the RET oncogene. Also, silencing ASCL1 in AD cells markedly reduced cell growth and motility. These results suggest that ASCL1 and RET expression defines a clinically relevant subgroup of ~10% of AD characterized by NE differentiation …" (emphasis added)



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About Kirk

Since becoming a lawyer in 1983, Kirk’s over 30 years of practice have focused on advising a wide range of corporations, associations, and individuals (as both plaintiffs and defendants) on both tort and commercial law issues centered around “mass torts.”


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