GZMB and breast cancer: ELISA data exhibited there were expression of IFN-γ, perforin, and granzyme B in Group 1 (MDA-MB-231 breast cancer cell lines alone) and Group 2 MDA-MB-231 breast cancer cell lines + MEPB), while there was expression of IFN-γ, perforin, and granzyme B in Group 3 (MDA-MB-231 breast cancer cell lines + NK cells).