TTF1 and neoplasm: Tumor cells are positive for GATA3, TTF-1, CD10, and PAX-8, negative or partially positive for ER, and negative for PR and WT1.2,6 Of these, MLA is positive for ≥2 mesonephric markers, and immunostaining is useful for diagnosis.6 In the present case, tumor cells were also positive for GATA3, TTF-1, CD10, and PAX-8, and this finding was extremely useful for making a diagnosis.