ESR1 and invasive breast carcinoma: In a study by Huang et al. on 101 cases of breast invasive carcinoma of no specific type, the overexpression of cyclin D1 was statistically correlated with early tumor stage (Stage I or II) (P = 0.047); 85% of these tumors were positive for ER (P < 0.0001) and 78.75% were positive for PR (P = 0.001).7