ESR1 and breast carcinoma: Interestingly, TENM4 overexpression has been detected in CSC-enriched tumorspheres that were derived from murine and human breast cancer cell lines, including 4T1 (murine TNBC), HCC-1806 (human TNBC), MDA-MB-231 (human TNBC), MCF-7 (human ER-positive) and SK-BR-3 (human HER2-positive).