TS Expression Could Guide Treatment in Nonsquamous NSCLC
“The combination of pemetrexed and cisplatin was superior to gemcitabine and cisplatin only in those non-squamous non–small-cell lung cancer (NSCLC) patients who were negative for the enzyme thymidylate synthase (TS), suggesting it could be used as a predictive marker to guide treatment.
“Previous research has shown that pemetrexed/cisplatin offers superior survival in nonsquamous NSCLC, while gemcitabine/cisplatin was better in squamous NSCLC. “A plausible mechanism for the histotype-dependent efficacy of pemetrexed-based chemotherapy can be explained by the presence of different levels of TS according to histologic types, with adenocarcinoma of lung cancer exhibiting a lower TS protein expression level than squamous cell carcinoma or neuroendocrine carcinoma,” wrote study authors led by Myung-Ju Ahn, MD, PhD, of Sungkyunkwan University School of Medicine in Seoul.
“TS is involved in de novo DNA synthesis, and inhibiting the enzyme leads to arrested cell proliferation; pemetrexed’s antitumor effects arise from inhibition of TS. The new study’s results were published online ahead of print in the Journal of Clinical Oncology.”