Strong MUC6 staining was linked to advanced pT stage (p = 0.0464), defective mismatch repair status and right‐sided tumor location (p < 0.0001 each) in colorectal cancer, as well as to high tumor grade (p = 0.0291), nodal metastasis (p = 0.0485), erb‐b2 receptor tyrosine kinase 2 positivity (p < 0.0001) and negative estrogen receptor (p = 0.0332)/progesterone receptor (p = 0.0257) status in breast carcinomas of no special type. The gene discussed is ESR1; the disease is colorectal cancer.