IL‐17–producing γ/δ T cells have indeed been implicated in tumor growth and metastasis in spontaneous models of breast cancer and pancreatic intraepithelial neoplasia (Coffelt et al. 2015; McAllister et al. 2014), as well as in multiple transplantable tumor models (Ma et al. 2014; Rei et al. 2014; Carmi et al. 2011). Here, IL17A is linked to breast cancer.