IL17A and invasive ductal breast carcinoma: We used a mouse model of breast cancer in which the γδ T cell–IL-17A–neutrophil axis is established (Coffelt et al., 2015; Wellenstein et al., 2019): the K14-Cre;Brca1F/F;Trp53F/F (KB1P) model of triple negative breast cancer, which develops invasive ductal carcinoma in one or more mammary glands at around 8 mo of age (Liu et al., 2007).