Analysis of an independent set of imatinib-treated GIST samples. A) Comparative analysis of tumoral areas from of GIST 6, 7 and 8, which resulted non-responding or responding to imatinib treatment. Panels 1-5, 6-10 and 11-15 refer to GISTs 6, 7 and 8 respectively. Panels 1, 6 and 11 represent non-responding areas; panels 2, 7 and 12 responding areas; panels 3, 8 and 13 show the inset areas of panels 2, 7, and 12. Arrows and arrowheads indicate inflammatory macrophages and lymphocytes, respectively, and asterisks residual tumor cells. Panels 4, 9 and 14 show the protein lysates prepared from adjacent tumor areas were separated onto SDS gels and stained with Coomassie-blu. Lane NR indicates the non-responding area and lane R indicates the responding area. Panels 5, 10 and 15 show NR and R protein lysates were probed with anti-SCGF and anti-actin antibodies, respectively. Note that in panels 5, 10 and 15 arrows refer to the actin band that is detected as a non-specific background band in anti-SCGF blot. As expected, due to the higher cellularity we observe a more intense actin band in NR samples than in R samples. B) Western blotting of SCGF expression in GIST 9-16 samples. GIST 9-13 represent protein lysates from non-responder GIST samples and GIST 14-16 protein lysates from responder samples. C corresponds to GIST 6 protein lysate. Samples were probed with both anti-SCGF and anti-actin antibodies. Arrow indicates actin band and asterisks SCGF band. In non-responder samples anti-SCGF detected exclusively the actin band.