ORIGINAL ARTICLE

Suppressor of cytokine signalling 2 (SOCS-2) expression in breast carcinoma

F Farabegoli¹, C Ceccarelli², D Santini² and M Taffurelli³

¹ Department of Experimental Pathology, University of Bologna, Via San Giacomo, 14, 40126 Bologna, Italy
² Institute of Anatomical and Pathological Histology, University of Bologna
³ Breast Cancer Surgical Unit, First Surgical Clinic, University of Bologna

Correspondence to:
Correspondence to:
Dr F Farabegoli
Department of Experimental Pathology, University of Bologna, Via San Giacomo, 14, 40126 Bologna, Italy; frbfl{at}alma.unibo.it

Aims: To investigate SOCS-2 (suppressor of cytokine signalling 2) protein expression in breast carcinoma samples in relation to biopathological parameters and survival.

Methods: A polyclonal antibody against SOCS-2 was used to study 50 archival breast carcinoma samples, collected from 1993 to 1995. The presence of SOCS-2 protein was investigated in relation to clinical and biological parameters used in breast cancer pathology. Fluorescence in situ hybridisation (FISH) was used to study whether SOCS-2 expression was related to SOCS-2 gene copy number.

Results: SOCS-2 protein was expressed in 34 of 50 breast carcinoma samples and was positively associated with low grade, low nuclear grade, and p27 protein. SOCS-2 expression was inversely related to Ki-67, cyclin A, retinoblastoma protein (pRb), and the epidermal growth factor receptor (EGFR). No relation with overall survival was demonstrated. SOCS-2 amplification was found in three samples. No relation between the number of FISH signals and SOCS-2 expression was found.

Conclusions: The significant correlation seen between SOCS-2 expression, grade, nuclear grade, p27, Ki-67, cyclin A, pRb, and EGFR labelling strongly supports the hypothesis that SOCS-2 loss might be related to cell proliferation and tumour growth in breast carcinoma. Gene copy number changes did not seem to play a role in SOCS-2 regulation and expression; other mechanisms might be involved and deserve further study.

Abbreviations: CIS, cytokine induced SRC homology 2 SH2 protein; EGFR, epidermal growth factor receptor; ER, oestrogen receptor; FISH, fluorescence in situ hybridisation; IHC, immunohistochemistry; %LIa, percentage of the labelled nuclear area over the total neoplastic nuclear area; OS, overall survival; PR, progesterone receptor; pRb, retinoblastoma protein; SOCS, suppressor of cytokine signalling

Keywords: breast carcinoma; fluorescence in situ hybridisation; suppressor of cytokine signalling 2; biopathological variables; prognosis

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