B2M and adenocarcinoma: The results of TCGA database analysis showed that the expression level of B2M mRNA was correlated with the histological subtypes of colon cancer, and the expression level of B2M mRNA in adenocarcinoma was lower than that in mucinous adenocarcinoma, and the difference was statistically significant (normal-vs-adenocarcinoma: p=1.34860012046545E − 10; normal-vs-mucinous-adenocarcinoma: p=2.019200E − 04; adenocarcinoma-vs-mucinous-adenocarcinoma: p=3.139800E − 02) (Figure 5).