Changes in RET expression have been discovered in 30-70% of invasive breast cancers and 50-60% of pancreatic ductal adenocarcinomas in addition to colorectal adenocarcinoma, melanoma, small cell lung cancer, neuroblastoma, and small intestine neuroendocrine tumors.
Stable overexpression of both mutant M918T and wild-type RET in two SCLC cell lines, H1048 and SW1271, activated ERK signaling, MYC expression, and increased cell proliferation, particularly by mutant RET.
Thus, although RET mutations appear unlikely to be an important step in the tumorigenesis of SCLC, the frequent expression of this gene suggests that RET may have a mitogenic role in a subset of SCLC cell lines.
We examined whether the novel point mutation from GCC (Ala) to GAC (Asp) at codon 664 in exon 11 of RET proto-oncogene, which we had found in two small cell lung carcinoma (SCLC) cell lines, existed in genomic DNA of tumor tissues of the two SCLC patients from whom these SCLC cell lines were derived.