Tissue non-specific alkaline phosphatase activity (TNAP). Total TNAP activity was detected at 405 nm wavelength, using p-nitrophenol as a substrate, in lymphoblasts, fibroblasts, PMC-42 mammary epithelial cells and breast tissue from both patients and control. Significant decreases were found in ALP activity in Mother 1 and Mother 2 lymphoblasts compared to control lymphoblasts. No differences were found between Mother 2 and control fibroblasts. Values represent mean of triplicates ± SEM, *p ≤ 0.05