The relationship between AR and TIL in breast cancer, especially in TNBC, has only recently raised interest in literature. Although the interactions between androgen signaling pathways and the immune infiltrate has been previously described in prostate and urinary bladder cancer, literature on this topic in breast cancer is scarce. (11, 12). One study analyzed the relationship between AR and TIL on 50 early TNBC patient samples, stages I to III, showing that as many as 70% of samples had a high TIL infiltration (> 80%) and 26% were AR positive. No statistically significant association was found between AR and TIL, but CD8 was shown to be more frequently present in AR positive tumors and CD4 in AR negative tumors. (6, 9) AR expression was more common in tumors with low Ki-67 but, unusually, in younger patients and in N + disease. High TIL infiltration was more common in aggressive tumors, with high grade and Ki-67 levels, but these tumors showed lower rates of disease recurrence and death. At the same time, they reported lower levels of CD8. (6) In 2019, another analysis examined the association between AR and TIL in 36 patients with early and metastatic TNBC. AR cut-off was ≥ 1%, and TIL were evaluated by HE staining with defining LPBC if sTIL ≥ 50%. AR were expressed in 19.4% of patients, with a median TIL of 15% in AR + and 33% in AR-, but without statistical significance regarding TIL values. (9) On the other hand, studies on CD3 T-cell markers showed they are more common in AR+, while CD20 is more common in AR-. The CD8 prevalence was not statistically different between AR + and AR-, but CD8 was significantly less present in the more advanced stages of disease (III and IV), compared to the lower (I and II). (14) A positive correlation between CD8 and CD3 was found, but with conflicting negative associations also described between CD3/CD20 and CD4/CD8. (7) An analysis of the AR prognostic role in 139 patients with early and metastatic TNBC, compared paired cases with present/absent disease dissemination, and AR status was identifed as a prognostic indicator, especially in TNBC patients not treated with systemic antineoplastic therapy. In the group receiving systemic treatment, the best outcome was in the low AR group (1 to 34%). The presence of sTIL was also included in the analysis, but without a report of a statistically significant correlation between the two parameters (8). A link between AR and the immune infiltrate in breast cancer was made by gene expression analysis in TNBC that defined three tumor subgroups, a non-basaloid, LAR subtype with a scarce immune response in about 20% of cases, BL with a scarce immune response and M2 macrophages, in almost 50% of TNBC cases and basaloid-enriched in strong immune responses and few M2 macrophages, in about 30% of cases. (15) In a study detailing AR and TIL effect on tastuzumab therapeutic response on 150 patients with metastatic HER2-positive breast cancer, AR expression was present in over 80% of cases (ER were positive in over 50% of cases) and was negatively correlated with M2 TAM (Tumor Associated Macrophages), and CD8 and CD3, but only in case of ER+. (16) Overall, AR were shown to be more pronounced in samples with low immune infiltrate, and vice versa, tumors with a high percentage of immune infiltrate were more often AR negative. More importantly, although only in exploratory analyses, patients with high AR expression and high immune infiltration were found to have a statistically significantly better OS, compared with tumors with low AR expression and high immune infiltrate, whereas there were no differences in OS in the other groups. It should, however, be noted that the study also found that the correlation between AR and immune infiltrate, that is, each of the individual IHC evaluated immune cell lines, differed in dependence of ER expression. (16, 17, 18, 19), Published data suggest that at least two key independent sources of biological information in TNBC (cellular and immune, and in addition to molecular data), have generated, a new immune classification of TNBC. (20) A study by Dieci et al. also demonstrated a prognostic role of AR in the TNBC cohort, noting that AR positive tumors were significantly associated with lower TIL values. On the other hand, although AR influenced prognosis, independent of disease stage, by adding TIL as a variable to the analysis, only TIL along with stage remained a strong independent prognostic factor. AR positive tumors had significantly worse DDFS, compared to AR negative tumors. (21) The association between high-AR tumors and antitumor regulatory T cells in general was also established, with AR-negative tumors positively correlated with antitumor immune cells, and AR positive tumors were inversely correlated, but had better survival. (22) The above results differ from those previously described in the TNBC and HER2 + populations, which once again indicates a more complex network of interactions of all these molecules defining breast cancer subtypes, and the modulatory influence of each on the correlation of the others. Finally, a recently published analysis showed that TIL in TNBC were a good prognostic indicator, that AR in TNBC were a negative prognostic indicator, that AR + tumors generally had poor TIL infiltration, and the worst DFS was in TIL- / AR + tumors. TIL in the TIL + / AR + subgroup appear to play a protective role, preventing disease recurrence and worse outcomes for these patients. (23)
No correlation of AR expression and TIL presence was observed in this analysis, however, a potential additional prognostic value was observed in the interaction of AR with TIL at the IM. The described heterogeneity of results with respect to the relationship of AR and TIL among different breast cancer subtypes could be somewhat expected, given the trend of different roles of each parameter individually in ER +, HER2 + and TNBC. It remains to be considered how many factors affect the relationships among the investigated parameters, the impact of which has not yet been defined or quantified. Modelled on the modulatory influence of, for example, the ER on the ratio of AR and TIL, similar can be thought about other molecular parameters, especially in the TNBC category. The described relationship of two apparently unrelated parameters, the luminal (AR+) subtype of tumor cells and the activation of the host intrinsic immune response, carries the potential in better defining TNBC prognosis.
The limitations of this research are associated with the retrospective model containing the possibility of systematic bias. This is an unicentric analysis, covering only patients treated for a certain period of time at a single center. Also, data such as more detailed pathohystological description, condition of margins on the postoperative sample, presence of DCIS component, LVI and PNI and some sociodemographic components such as BMI, family history and comorbidity were missing for a larger number of patients in the sample, and these variables were not included in the final analysis. In this analysis, parameters such as molecular markers for TNBC, such as CK5/6, EGFR, are missing, meaning TNBC was not categorized into basaloid, 5NP, luminal.., what certainly affects the expression of the analyzed variables in this study. Overall, the sample had a small absolute number of AR positive, especially AR highly positive patients, so we did not obtain statistical significance in the multi-parameter analyses as well as in the survival analyses for the high-AR category. However, this study is one of the first and analyses of AR and TIL in a homogeneous cohort of patients with early TNBC using spatial TIL analysis. The associations between AR and TIL were extremely low (ρ < 0.08) and negative. Based on sample size and empirical AR distribution, reliable conclusions on whether the variables are independent are difficult, but our results give ground to an assumption that larger samples may show a positive correlation, especially after a value of 60 with sTIL at IM and 40 with iTIL at IM.