Recent in situ hybridization experiments have shown a high content of
IGF-II mRNA in
breast cancer stroma. The aim of this study was to examine the relationship between
IGF-II protein expression and several prognostic parameters in 75 infiltrating
ductal carcinomas (IDC) of the breast. Tissue sections were evaluated for proliferative activity,
IGF-II protein, ER, PgR, p53, and p21 expression using immunohistochemical procedures. The degree of stromal proliferation was assessed. Menopausal status, axillary lymph node involvement and nuclear grade were known. Thirty-five patients (44.3%) were premenopausal and 47 (62.6%) had
lymph node metastases. Marked stromal proliferation was found in 34 (45.3%) specimens and high nuclear grade in 20 (26.5%). Eighteen
tumors (24%) showed no
IGF-II immunostaining. In the positive cases,
IGF-II was detected both in the
tumor stroma and in the cytoplasm of epithelial
cancer cells: a high
IGF-II content was found in 12 specimens (16.0%), a low content in 14 (18.7%) and a moderate content in 31 (41.3%). Twenty-four
tumors (32.0%) showed high proliferative activity. Both ER and PgR were expressed in the nucleus of
cancer cells: 49
tumors (65.3%) were ER positive (ER+) and 34 (45.3%) PgR positive (PgR+). p21
protein was detected in 37
tumors (49.6%) and p53 in 12 (16%).
IGF-II protein was not correlated with menopausal status,
lymph node metastases, nuclear grade, proliferative activity, ER or p53. In contrast,
IGF-II correlated strongly with stromal proliferation (p=0.008), PgR (p=0.03) and p21 (p=0.01). This study demonstrates that in IDC of the breast
IGF-II protein is expressed in the epithelium and stroma of the majority of
tumors and is correlated with stromal amount, PgR and p21 expression. These preliminary results indicate that
IGF-II expression in
breast cancer is connected with two important regulators of
breast cancer growth and differentiation.