FAP and colorectal carcinoma: Furthermore, a direct correlation was demonstrated between GREM1 mRNA levels and both fibroblast activation protein (FAP) mRNA (Pearson r = 0.7117, p< 0.0001 Figure 2C left) or ESTIMATE StromalScore (Pearson r = 0.7448, p< 0.0001; Figure 2C right) in transcriptional data from primary CRC tumour tissue (GSE39582 [23]).