Intra-Tumoral Lymphocytes in Breast Cancer: Real Perspectives?

Background : During the conference of ASCO 2015, there was no consensus about TIL role in beast cancer and no recommendations concerning the microscopic assessment of TIL. In fact, the patients could be put on anti-PD1 drugs without the necessity of highlighting PD1 positive cells by using immunohistochemistry. Nevertheless, many questions about the prognostic impact of TIL, the methods of assessment, the type of TIL to count remain unresolved. Material and Methods : We performed a review of the literature on the sites : Pubmed and Cochrane. We used the key-words : �TIL in cancer�; �TIL in breast cancer� and �prognostic impact of TIL in breast cancer�. Results : According to our inclusion and exclusion criteria, thirty eight articles were retained. Our review of the literature showed that assessing TIL in high grade tumors seem unnecessary. They seem available in intermediate graded tumors. In neo-adjuvant and adjuvant conditions, CD3+ lymphocytes seem to be correlated to a good response to chemotherapy. After a chemotherapy, quantification T reg lymphocytes CD4 + FOXP3+ seems helpful because the decrease of their number is correlated to a good prognosis. Conclusion : The role of TIL in breast cancer is clearly established. The mechanisms of immune escape induced to discovery of immune therapy. The role of the microscopic examination and the subtyping of TIL using immunohistochemistry hasn�t been clearly established. Through this review of the literature, we tried to establish a diagram highlighting the different subtypes of TIL to evaluate and their prognostic impact.