PTK6 and Fibroadenoma: As expected, IHC analysis of the human breast tumor tissue array revealed Brk expression in only one (a fibroadenoma) of the 84 non-transformed tissue samples (Figure 9a), and in Brk-positive tumors, Brk expression was significantly associated with increased phospho-p38 (Table 2); the samples in this group were mostly derived from premenopausal women.