An exploratory integrative analysis of plasma transcriptomic and proteomic predictors of response to total...

LARC patients exhibit heterogeneity in their response to total neoadjuvant therapy (TNT). This study aims to screen and identify plasma biomarkers associated with treatment response to TNT in patients with locally advanced rectal cancer (LARC) to predict pathological complete response (pCR).

Pre-treatment plasma RNA sequencing and functional annotation were performed in six patients with LARC (three pCR and three non-pCR) to identify differentially expressed genes (DEGs) associated with TNT response. The Olink^® Target 96 Oncology II panel was employed to validate a subset of DEGs at the protein level in 61 patients with LARC (20 pCR vs 41 non-pCR), 6 patients with rectal adenoma (RA), and 6 healthy participants. Correlations between pretreatment plasma differentially expressed proteins (DEPs), clinicopathological characteristics, and TNT-response in LARC patients were analyzed.

Compared to the non-pCR group, 365 DEGs were upregulated, and 198 were downregulated in the pCR group. These genes are involved in pathways related to cell growth and death, signal transduction, metabolism, the immune system, insulin secretion, mitophagy, and neutrophil extracellular trap formation. The transcriptomic analysis was conducted in a limited discovery cohort, and these DEGs identified should be interpreted with extreme caution due to the high risk of false discovery. Plasma levels of Fas ligand (FASLG), CD160, andLY6/PLAUR domain containing 3 (LYPD3) in the pCR group were higher than those in the non-pCR group. Receiver operating characteristic (ROC) curve analysis showed that a multi-marker panel consisting of FASLG, CD160, and LYPD3 was superior to three individual indicators in predicting pCR, with an area under the curve (AUC) of 0.791 (95% CI, 0.668-0.885). According to the optimal cutoff value of the multi-marker panel, all LARC patients were stratified into high (n=34, 55.7%) and low (n=27, 44.3%) expression groups. Statistical analysis indicated that high expression group was associated with a higher proportion of EMVI-negative status and a higher pCR rate. High expression of multi-marker was associated with pCR in multivariate analysis.

The multi-marker panel consisting of FASLG, CD160, and LYPD3 may serve as a candidate predictor of treatment response in LARC patients undergoing TNT, warranting further validation in larger, multicenter cohorts.