A new tumor immune-related gene signature may help take the guesswork out of prognostication in patients with early-stage non–small cell lung cancer (NSCLC), according to a retrospective cohort study.
“Various components of the immune system have been shown to be a determining factor during cancer initiation and progression,” note the investigators, who were led by Bailiang Li, PhD, of Stanford (Calif.) University. “Recent immunotherapies targeting specific immune checkpoints such as programmed death 1 or programmed death ligand 1 have demonstrated a remarkable, durable response in NSCLC. Certain histopathologic patterns, such as intratumoral infiltration by cytotoxic lymphocytes, have also been associated with better prognoses in several cancer types, including NSCLC.”
For the study, the investigators developed and validated an immune-related gene signature using frozen tumors from 2,414 patients with stage I or II nonsquamous NSCLC from 19 public cohorts who underwent resection with negative margins and did not receive any neoadjuvant or adjuvant therapy.
The new signature contained 25 gene pairs consisting of 40 unique immune-related genes, Dr. Li and associates report (JAMA Oncol. 2017 Jul 6. doi: 10.1001/jamaoncol.2017.1609).
Processes such as chemotaxis were enriched among the included genes.
The signature significantly stratified patients into groups that have high and low risks of death during follow-up, both across and within subsets with stage I, IA, IB, or II disease. Relative to counterparts falling into the signature-defined low-risk group, those falling into the signature-defined high-risk group had roughly twice the risk of death after adjustment for clinical and pathologic characteristics, with a hazard ratio range of 1.72 (P less than .001) to 2.36 (P less than .001).
Accuracy of the immune signature exceeded that of two commercialized gene signatures for estimating survival in similar validation cohorts (mean concordance index [C-index], 0.64 vs 0.53 and 0.61).
Moreover, the combination of the immune signature with clinical factors outperformed the signature alone (mean C-index, 0.70 vs 0.63) and another commercialized clinical-molecular combination signature (mean C-index, 0.68 vs 0.65).
“The proposed immune-related gene pair–based signature is a promising prognostic biomarker in nonsquamous NSCLC, including early-stage disease,” concluded the investigators. “Prospective studies are needed to further validate its analytical accuracy for estimating prognoses and to test its clinical utility in individualized management of nonsquamous NSCLC.”