An ultrasound-guided tru-cut core biopsy was subsequently performed, diagnosing invasive carcinoma of no special type (NST), moderately differentiated (G2), strongly positive for estrogen and progesterone receptors (ER 99%, PgR 99%), with a low proliferative index (Ki-67 12–14%) and no oncoprotein C-erbB2 overexpression (HER2 0). Here, PGR is linked to invasive carcinoma.