Whether PDL1 or TILs have any indication for prognosis in male breast cancer (MBC) patients remains unknown. In this study, we investigated the relationship between the expression and degree of PDL1 and TILs and evaluated the prognostic value of these factors in MBC.
We retrospectively identified 150 MBC patients diagnosed between 2003 and 2013 at Salah Azaïz Cancer Institute. PDL1, Stromal (str) CD8+ and CD4+ TILs were evaluated immunohistochemically. TILs levels were evaluated following 2014 International TILs Working Group guidelines.
Fifty three percent of MBC patients had low str-TILs and 47% had moderate str-TILs. No lymphocyte predominant breast cancer was identified. Only 12% of MBC patients had high str-CD8+TILs and 11% had high str-CD4+TILs. TNBC subtype and HER2 enriched tumors had higher median levels of str-CD8+TILs, str-CD4+ TILs and str-TILs at diagnosis. On univariate analysis, higher levels of str-CD8+TILs, str-CD4+ TILs and str-TILs were associated with better OS (p = 0.035, p = 0.043 and p = 0.040 respectively). Multivariate analysis identified str-CD8+ TILs and str-TILs as independent prognostic factors for OS ([HR = 0.851 (0.706-0.997), p = 0.000] and [HR = 0.69 (0.43-0.96), p = 0.045] respectively). High expression of PD-L1 was observed in 64.5% of MBC samples. Patients with high PD-L1 expression had significantly shorter overall survival (OS) than patients with low expression (p = 0.002, hazard ratio HR = 5 [2.624 –10.642]). Multivariate analysis identified PD-L1 as independent prognostic factor for OS (p < 0.001, HR = 0.775 [0.680–0.870]).
PD-L1 expression, Str-CD8+ T cells and str-TILs represents promising novel biomarkers with prognostic significance in MBC. Thus, successful inclusion of these markers in prognostic clinical models is becoming a realistic hope in MBC.
Clinical trial identification
Legal entity responsible for the study
Institut Salah Azaïz.
Has not received any funding.
All authors have declared no conflicts of interest.