The distribution of TIMP3 transcripts in human breast carcinomas and normal tissues detected by in situ RNA hybridization
Bright field (a–c, e, g) and dark field (d, f, h) photomicrographs of paraffin-embedded tissue sections stained with toluidine blue after hybridization with 35S-labeled antisense (a, c–h) and sense (b) TIMP3 transcripts derived from a 1976-bp S6 TIMP3 subclone including 5′-UTR, coding sequences, and 1063 bp of 3′-UTR sequence are shown. Identical patterns of labeling were obtained using riboprobes derived from the entire 4579-bp TIMP3 cDNA (data not shown). (a) Placenta (36 weeks gestation) showing strong labeling of endometrial decidual cells, (b) The corresponding region of the same placental sample hybridized with the sense TIMP3 riboprobe. (c, d) An infiltrating ductal breast carcinoma showing strong labeling of fibroblastic cells in close contact with small islands of cancer cells, which are themselves not labeled. (e, f) In situ carcinoma of cribriform subtype, in which positive labeling is clearly associated with fibroblastic cells around the duct, while carcinoma cells within the duct are not labeled, (g, h) In situ carcinoma of micropapillary subtype, in which TIMP3 transcripts were strongly identified within stromal cells, while cells of the epithelial compartment were not labeled. Magnifications were 50× (g, h), 125× (a, b, e, f), and 250× (c, d). Exposure times were 14 (a, e–h), 21 (c, d), and 32 days (b).