Insulin-like growth factor system gene expression in cervical scrapes from women with squamous intraepithelial lesions and cervical cancer.
BACKGROUND
There is ample evidence that the insulin-like growth factors (IGF) system is involved in the development of several types of cancer. The aim of this study was to evaluate the expression levels of IGF-I, IGF-II, IGF binding protein 3 (IGFBP-3) and IGF-I receptor (IGF-IR) in exfoliated cervical cells in cervical carcinogenesis.


METHODS
mRNA levels of IGF-I, IGF-II, IGFBP-3 and IGF-IR were assessed by real-time PCR in 105 cervical scrapes obtained from 16 patients diagnosed with low-grade squamous intraepithelial lesions (LSIL), 24 with high-grade SIL (HSIL), 23 with cervical cancer, and 42 from controls with normal Papanicolau (Pap) test.


RESULTS
IGF-I mRNA levels were very low and no significant differences were seen between control and other groups. IGF-II mRNA levels were significantly lower in LSIL than in control group (median [arbitrary units]: 0.38 vs. 2.42, P=0.006) but its expression in HSIL and cervical cancer was similar to the one observed in controls. IGFBP-3 mRNA levels were significantly lower in cancer than in controls (median [arbitrary units]: 0.43 vs. 0.73, P=0.03). We observed a decrease in IGF-IR gene expression as the SIL degree increased (median for controls, LSIL, HSIL, and cervical carcinoma [arbitrary units]: 31.24, 9.08, 8.95, and 3.56, respectively). IGF-IR mRNA levels were significantly lower in HSIL and cervical cancer in comparison with controls (P=0.043 and P<0.001, respectively).


CONCLUSIONS
The present observations suggest that a reduced expression of IGFBP-3 and IGF-IR can be associated with progression to cervical cancer; the specific role played by the IGF-IR in this process remains unclear.
Serrano
Martha-Lucía
ML
Grupo de Investigación en Biología del Cáncer, Instituto Nacional de Cancerología, Bogotá, Colombia.
Sánchez-Gómez
Myriam
M
Bravo
María-Mercedes
MM
D000328:Adult; D000368:Aged; D005260:Female; D015870:Gene Expression; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D008875:Middle Aged; D018307:Neoplasms, Squamous Cell / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D017526:Receptor, IGF Type 1 / Q000235:genetics*; D002583:Uterine Cervical Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D014626:Vaginal Smears; D002578:Uterine Cervical Dysplasia / Q000737:chemistry / Q000235:genetics* / Q000473:pathology
C515497:IGFBP3 protein, human; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1