The predictive effect of the CD155-TIGIT immune checkpoint axis complex on neoadjuvant chemotherapy efficacy in triple-negative breast cancer: A preliminary study

BackgroundThe CD155-TIGIT axis, a breast cancer progression biomarker, underscored neoadjuvant chemotherapy (NAC) response variability in triple-negative breast cancer (TNBC), urging biomarker-based patient stratification for timely therapy.MethodsThirty-nine TNBC patients who received NAC were recruited. The expression of TIGIT, CD155, CD226, and CD96 on tumoral and stromal cells in the tumor microenvironment was detected by immunohistochemistry, and their relationships with NAC response were explored.Results10.3% patients exhibited grade 1 (G1) response to NAC, and 20.5% achieved a complete pathological response. Notably, CD155 and CD96 were predominantly detected on tumor cells, whereas CD226 and TIGIT were predominantly detected on stromal cells. The expression of these markers did not significantly correlate with response to NAC (<i>p</i> > 0.05), and each individual marker lacked predictive power for determining NAC therapeutic efficacy (<i>p</i> > 0.05). However, a specific combination of tumoral cells expression of CD226(≥4%), CD155(≥40%), and CD96(≥35%), coupled with TIGIT expression on tumoral (<35%) and stromal cells (<12.5%), was able to identify patients with G1 response to NAC.ConclusionExpression levels of TIGIT/CD155/CD226/CD96 on tumoral and stromal cells might collectively serve as predictive biomarkers for NAC response in TNBC. This implied that CD155-TIGIT axis could be prospectively applied clinically to identify NAC-resistant TNBC patients.