Although cytoplasmic protein tyrosine kinase 6 (PTK6; breast tumour kinase (BRK)) is overexpressed in up to 86% of breast carcinomas (Ostrander et al, 2007; Harvey et al, 2009; Brauer and Tyner, 2010), its physiological role is rather unclear. The gene discussed is PTK6; the disease is breast carcinoma.