INSULIN-LIKE GROWTH FACTOR-I EXPRESSION IN NORMAL AND DISEASED ENDOMETRIUM Eugenio MAIORANO 1 *, Giuseppe LOVERRO 2 , Giuseppe VIALE 3 , Teresa GIANNINI 4 , Anna NAPOLI 1 and Elda PERLINO 3 1 Istituto di Anatomia Patologica, Universita ` degli Studi di Bari, Bari, Italy 2 Clinica Ostetrica e Ginecologica II, Universita ` degli Studi di Bari, Bari, Italy 3 Divisione di Anatomia Patologica e Medicina di Laboratorio, Istituto Europeo di Oncologia, Universita ` degli Studi di Milano, Milan, Italy 4 Centro Studi Mitocondri e Metabolismo Energetico, C.N.R., Bari, Italy W hile the role of steroid hormones in the regulation of endometrial proliferation and differentiation is well estab- lished, the effects of growth factors and their receptors in normal and neoplastic endometrium remain a matter of debate. Previous studies have documented the positive ef- fects of insulin-like growth factor-I (IGF-I) on epithelial cell proliferation and the active production of this growth factor in endometrial tissues. In view of decreased expression of transforming growth factor-1 (TGF-1), an antagonist of IGF-I, in endometrial carcinoma, we investigated the expres- sion of IGF-I, at both the mRNA and protein levels, and the immunoreactivity for type I IGF-I receptor in 30 formalin- fixed, paraffin-embedded tissue samples of normal and neo- plastic endometrium, in order to possibly clarify the role of IGF-I in endometrial proliferation and differentiation. Our results demonstrate a reduced expression of IGF-I mRNA in endometrial carcinomas compared with non-neoplastic tis- sues, despite equivalent immunohistochemical expression of IGF-I and IGF-I receptor. Our data suggest that IGF-I and its corresponding receptor may not be directly involved in endometrial cancer cell proliferation and differentiation in vivo, though other components of the IGF-I system ( e.g., IGF binding proteins) may affect endometrial malignant transfor- mation and tumor progression. Int. J. Cancer 80:188–193, 1999.  1999 Wiley-Liss, Inc. Unbalanced estrogenic stimulation of the endometrium is one of the main responsible factors of endometrial hyperplasia and carcinoma (Gurpide, 1991); nevertheless, the progression from normal cells to malignancy is also likely to require both the activation of oncogenes and the inactivation of tumor suppressor genes (Cline, 1996). Furthermore, abnormal regulation of several genes, including those encoding for growth factors and their receptors, frequently occurs in different cancers, including endome- trial carcinoma (Berchuck and Boyd, 1995). Both stromal and epithelial endometrial cells synthesize cyto- kines and growth factors which possibly modulate endometrial proliferation and differentiation (Smith, 1994). Several cytokines and growth factors such as insulin-like growth factor-I (IGF-I), transforming growth factor- (TGF-), tumor necrosis factor- (TNF-), colony stimulating factor-1 (CSF-1) and interleukins-1 and -6 (IL-1/6) actively regulate endometrial growth and differen- tiation, interacting with steroid hormones (Giudice, 1994). IGF-I is a growth hormone-dependent growth factor with a molecular weight of 7,650 kDa (Daughaday and Rotwein, 1989) which promotes mitosis in several epithelial cell types (Jones and Clemmons, 1995). Hepatocytes and many other cell types actively synthesize IGF-I, which regulates cell growth in an autocrine or paracrine fashion (D’Ercole et al., 1984). Moreover, several neoplastic cell types express IGF-I mRNA (Daughaday, 1990; Macaulay, 1992), and the autocrine production of growth factors and their receptors may significantly affect tumor differentiation and progression (Abbott et al., 1992). IGF-I and IGF-II are also involved in the regulation of endometrial growth (Giudice et al., 1993) and possibly in interactions between epithelial and stromal compartments of the endometrium (Talavera et al., 1990; Giudice et al., 1992). The mitogenic effects of IGF-I on epithelial cells are counter- acted by the negative regulation of cell growth of TGF- (Fausto, 1991). We have previously demonstrated a reduced expression of TGF-1 mRNA, as opposed to increased immunohistochemical expression of TGF-1 in endometrial carcinoma compared with non-neoplastic endometrium (Perlino et al., 1998). Our present study was aimed at evaluating the expression of IGF-I, at both the mRNA and protein levels, by means of Northern blotting and immunohistochemistry in the same normal and neoplastic endometrial tissues investigated for TGF-1 expression, to possibly elucidate the role of IGF-I in endometrial carcinogen- esis. An immunohistochemical study on IGF-I receptor was also performed on the same tissue samples to correlate the expression of the growth factor with the cellular localization of its receptor. MATERIAL AND METHODS Patients This study was performed on consecutive tissue samples ob- tained from 30 women admitted to the II Department of Obstetrics and Gynecology of the University of Bari in the years 1995–1996. The patients were divided into 3 groups: Group 1 included 10 normally menstruated women (mean age: 46.5  3.6 years; range: 42–53 years) with subserosal leiomyomas who underwent hysteroscopy with microbiopsy, in order to exclude the presence of relevant endometrial lesions, and subsequent simple hysterectomy. Group 2 included 5 postmenopausal women (mean age: 60.6  2.9 years; range: 55–63 years; median postmenopausal age: 8.8  3.3 years) who underwent hysterectomy with bilateral sal- pingo-oophorectomy for uterine prolapse; in these women, previ- ous hysteroscopy with microbiopsy had excluded relevant endome- trial lesions. Group 3 included 15 women (mean age: 62  11 years; range: 39–81 years) with histologically proven endometrial adenocarci- noma who underwent hysterectomy, bilateral salpingo-oophorec- tomy and selective pelvic lymphadenectomy. All patients included in our study had not received hormonal therapy prior to surgery and should not have manifested concomi- tant ovarian lesions. Informed consent was obtained from all patients for the inclusion in the study. Tissue processing Quickly after surgical removal of the uterus, an endometrial sample was taken from all specimens, snap-frozen and cryopre- Grant sponsors: Associazione Italiana per la Ricerca sul Cancro (A.I.R.C.) and Ministero per l’Universita ` e la Ricerca Scientifica e Tecnologica (M.U.R.S.T.). *Correspondence to: Istituto di Anatomia Patologica, Policlinico, Piazza G. Cesare, 11, I-70124 Bari, Italy. Fax: (39) 80-5478-280. E-mail: emaiorano@anatopat.uniba.it Received 25 April 1998; Revised 20 July 1998 Int. J. Cancer: 80, 188–193 (1999)  1999 Wiley-Liss, Inc. Publication of the International Union Against Cancer Publication de l’Union Internationale Contre le Cancer