The levels of CD33+ myeloid‐derived suppressor cells (MDSCs) and Yes‐associated protein 1 (YAP1) and phosphatase and tensin homologue (PTEN) expression in patients with colorectal cancer (CRC). (a) Immunohistochemical analysis of CD33, YAP1 and PTEN in tumour and tumour‐adjacent tissues from the same CRC patients. (b–d) Statistical analysis revealed that the levels of CD33+ MDSCs and YAP1 were significantly higher in tumour tissues than in tumour‐adjacent tissues from the same patient, whereas the level of PTEN was significantly lower in tumour tissues than in tumour‐adjacent tissues from the same patient (n = 40, P < 0·05). (e–g) Correlation analysis between YAP1 or PTEN and tumour‐infiltrating CD33+ cells. Our observations indicated that YAP1 expression was significantly positively associated with the number of tumour‐infiltrating CD33+ cells (e, R = 0·205, P = 0·005, n = 145), whereas PTEN expression was significantly negatively associated with the number of tumour‐infiltrating CD33+ cells (g, R = −0·152, P = 0·040, n = 145) and YAP1 expression (f, R = −0·149, P = 0·042, n = 145). The statistical analysis was performed using Pearson's correlation coefficient and linear regression. R, Spearman's correlation; P, significance of correlation.