Figure 1.

Stromal tumor infiltrating lymphocytes (TILs) within the central tumor (CT) of pet rabbit mammary carcinomas. Illustrated are two representative tumor areas with very few stromal TILs (A,A’) and multifocal aggregates of stromal TILs (B,B’), respectively. (A,A’) Grade I carcinoma with a tubular growth pattern and moderate secretory activity. Occasional stromal TILs (less than 1%) are present in the 20× objective field of view (FOV) shown in A. The rectangular area delineated in A is illustrated in A’ in higher magnification. Individual rare stromal TILs are labelled by arrows. (B,B’) Stromal TILs (asterisks) form multifocal aggregates that dissect between tubular structures lined by tumor cells (arrowheads). The 20× objective FOV present in B contains an estimate of 50% stromal TILs. The area delineated by a rectangle is shown in B’ in higher magnification.