In addition, ALDH1A3, COL1A2, FADS1, SFRP2, SULF1, and THBS2 were found to be significantly (p < 0.01) differentially expressed in tumour samples but not in adenomas compared to healthy samples (Fig. 1, Table 2, Additional file 3: Figure S1, Additional file 4: Table S3). Here, SULF1 is linked to adenoma.