Epigenetic inactivation of FOXF1 in primary invasive breast tumors. A, MSP analysis was performed on normal mammoplasty tissues (Mam-1 to -8), normal organoids (Org-1 to -6), normal peripheral white blood cells (WBC-1 to -9) and primary invasive ductal carcinomas (IDC-1 to -16). B, Bisulfite sequencing analysis of the FOXF1 promoter in invasive ductal carcinomas. FOXF1 expression status in these primary IDC tumors is shown on the right side of the figure; arrow pointing down: underexpression, (+): expression, (−): no expression, nd: not determined. C, Quantitative RT-PCR analysis of FOXF1 expression in normal breast organoids vs. primary breast IDC tumors with methylated FOXF1 promoter. D, Immunohistochemistry analysis of FOXF1 protein expression in normal breast tissue and primary breast IDC tumors with or without methylated FOXF1 gene. A summarized result from 26 IDC samples is shown on the bottom panel.