ESR1 and neoplasm: In our analysis, CL BCs displayed only one feature common with basal tumors (ERBB2 status), whereas differences were significant regarding all the other features: age at diagnosis (less young patients in CL cases), pathological type (less often ductal or medullary, but more often metaplastic in CL), grade (less often grade 3 in CL), tumor size (less often pT2-3 in CL), lymph node status (more often positive in CL), ER and PR status (less often negative in CL), and triple-negative status (less frequent in CL).