Immunohistochemical analysis of serial human ovarian tumor sections for EGFR activation, MMP-9, and E-cadherin. Serial sections of primary ovarian tumor samples were stained with antibodies to active (phospho-) EGFR, MMP-9, or E-cadherin (as indicated) and scored as described in “Materials and Methods”. EGFR activation was significantly positively correlated with MMP-9 expression (Spearman's rho=.429, p<.0001), and examination of serial tumor sections revealed numerous areas with reduced levels of E-cadherin that co-localized with strong positive staining for activated EGFR and MMP-9. (A) Clear cell carcinoma; (B) endometrioid; (C) serous; (D) mucinous. (i-iii)-200× magnification; (iv-vi)-400× magnification. Black box (i) designates area magnified in (iv-vi).