In 1995, Luparello and collaborators [15] tested the effect of different PTHrP domains on the proliferative behavior of 8701-BC, a cell line derived from a primary ductal infiltrating carcinoma (d.i.c.)of the human breast and thereby being more representative of the heterogeneity present in the tumor cell population in vivo [16]. The gene discussed is PTHLH; the disease is breast cancer.