PTGDR and adenoma: Gene expression changes of BCL2, CYP27B1, COL1A2, FADS1, and SULT1A1 were significant (p < 0.05) only in tumours compared to healthy samples, while CDX1, ENTPD5, PTGDR ,and TIMP1 showed gene expression difference in both normal vs. adenoma and normal vs. tumour comparisons (Fig. 1, Table 2, Additional file 4: Table S3).