ERBB2 and cancer: The underlying biological basis for the 100% distant metastasis-free interval that are luminal tumors smaller than 1 cm, detected in mammogram screening, with non-palpable presentation and negative lymph nodes, would be nonprogressive preclinical cancers and we can also assume that, due to their biological characteristics, tumors with basal subtypes and HER2 would be progressive preclinical cancers and would become nonprogressive with treatment.