Figure 2.

Patterns of procollagen α1(I) and α1(IV) expression in normal mucosa and CC as revealed by in situ hybridization with [³⁵S]-labeled RNA probes. B, C, and D represent adjacent serial sections of the same biopsy (case no. 8). Procollagen α1(I)-specific labeling is displayed by cells of the subepithelial myofibroblast sheet (curved arrows) and the lamina propria (arrowheads) of normal colonic mucosa (A). In CC, the same probe reveals cells with high transcripts levels in an almost linear distribution underneath the surface epithelium (B and C). A weak background signal is seen after hybridization with the sense (control) probe (D). As compared to normal mucosa (E), elevated levels of procollagen α1(IV) transcripts are found in myofibroblasts in a linear distribution underneath the surface epithelium in CC (arrows, case no. 6, F). Autoradiographic exposure time 14 days (A–D) and 36 days (E, F). Original magnification, ×100 (A, B, E, F) and ×50 (C, D).