NRG1 and neoplasm: To test this, we used quantitative RT-PCR to measure gene expression changes in tumor-promoting fibroblasts of the five factors (CCL-2, -7, -8, AREG, and STC1) that we had determined all had functional relevance, along with two others factors (NRG1; MIM: 142445 and WISP1) that also were induced in the system.