Introduction:Uterine neoplasms are the most common spontaneous tumours in the rabbit and most cases are adenocarcinomas of the endometrium (Weisbroth, 1974). The incidence of this tumour increases with age and has been reported to reach 60% in animals over 4 years (Brown, 2002). The neoplastic proliferation of endometrial epithelium is influenced by estrogen and progesterone. Pseudopregnancy is commonly seen in the mature rabbit and is characterized by prolonged maintenance of the corpora lutea and secretion of progesterone in the absence of conceptus (Knobil, 1998). This suggests that non-neutered female rabbits are predisposed to the development of uterine cancer. Material and methods: Nine uterine tumors (4 adenomas and 5 adenocarcinomas) were selected and submitted for immunohistochemistry (IHC)with antibodies to: CK19, Progesterone (PR), MIB-1 (anti Ki67) and telomerase (TEL). Results: All four cases of adenoma were positive to PR, with moderate to strong nuclear staining; all cases were negative to CK19; staining with MIB-1 was observed in all cases with 2 showing less than 25% of positive nuclei and 2 more with 25-50% positive nuclei; 2/4 were positive to TEL. Among adenocarcinomas 4/5 cases were positive to PR; all were moderately to intensely positive to CK19; staining with MIB-1 was observed in all cases with 4/5 cases showing less than 25% of positive nuclei and 1/5 cases with 25-50% positive nuclei; all cases were negative to TEL. Discussion: It is well-known that hormones play a major role in the development of abnormal proliferative lesions of the endometrium and in women with uterine adenocarcinomas several studies have shown that the presence and quantity of steroid receptors are correlated with histologic differentiation and survival (Silverberg et. al., 1992). In the present study the expression of progesterone was similar in both adenomas and adenocarcinomas. This suggests that progesterone promotes neoplastic transformation, but does not influence the behaviour of the tumour. Proliferative activity was evaluated by means of the expression of MIB-1. Proliferation was low in both benign and malignant tumors; in most cases (7/9) the percentage of proliferating cells was lower than 25%. This indicates that the proliferative activity is not correlated with malignancy. Telomerase expression suggests that it plays a key role in the progression of several tumours. In this study nuclear telomerase expression was detected in only two cases of adenoma.CK19 expression was investigated and resulted positive in all malignant cases, whereas it was completely absent in benign tumors. On the basis of the obtained results some tumours do not seem to arise from the uterine glands as appears from the negativity to CK19, but from the luminal epithelium. Hormonal therapy of uterine carcinomas in rabbits can be considered more appropriate than the antiblastic therapy, considering the low proliferative activity of endometrial malignant tumors. The low expression of telomerase in adenomas and its absence in adenocarcinomas does not support the importance of telomerase dependence of malignant transformation and the employment of anti-telomerase therapeutic approaches.

Immunohistochemical findings of uterine tumours in the rabbit.

VINCI, ANNACHIARA;BACCI, BARBARA;BENAZZI, CINZIA;SARLI, GIUSEPPE
2008

Abstract

Introduction:Uterine neoplasms are the most common spontaneous tumours in the rabbit and most cases are adenocarcinomas of the endometrium (Weisbroth, 1974). The incidence of this tumour increases with age and has been reported to reach 60% in animals over 4 years (Brown, 2002). The neoplastic proliferation of endometrial epithelium is influenced by estrogen and progesterone. Pseudopregnancy is commonly seen in the mature rabbit and is characterized by prolonged maintenance of the corpora lutea and secretion of progesterone in the absence of conceptus (Knobil, 1998). This suggests that non-neutered female rabbits are predisposed to the development of uterine cancer. Material and methods: Nine uterine tumors (4 adenomas and 5 adenocarcinomas) were selected and submitted for immunohistochemistry (IHC)with antibodies to: CK19, Progesterone (PR), MIB-1 (anti Ki67) and telomerase (TEL). Results: All four cases of adenoma were positive to PR, with moderate to strong nuclear staining; all cases were negative to CK19; staining with MIB-1 was observed in all cases with 2 showing less than 25% of positive nuclei and 2 more with 25-50% positive nuclei; 2/4 were positive to TEL. Among adenocarcinomas 4/5 cases were positive to PR; all were moderately to intensely positive to CK19; staining with MIB-1 was observed in all cases with 4/5 cases showing less than 25% of positive nuclei and 1/5 cases with 25-50% positive nuclei; all cases were negative to TEL. Discussion: It is well-known that hormones play a major role in the development of abnormal proliferative lesions of the endometrium and in women with uterine adenocarcinomas several studies have shown that the presence and quantity of steroid receptors are correlated with histologic differentiation and survival (Silverberg et. al., 1992). In the present study the expression of progesterone was similar in both adenomas and adenocarcinomas. This suggests that progesterone promotes neoplastic transformation, but does not influence the behaviour of the tumour. Proliferative activity was evaluated by means of the expression of MIB-1. Proliferation was low in both benign and malignant tumors; in most cases (7/9) the percentage of proliferating cells was lower than 25%. This indicates that the proliferative activity is not correlated with malignancy. Telomerase expression suggests that it plays a key role in the progression of several tumours. In this study nuclear telomerase expression was detected in only two cases of adenoma.CK19 expression was investigated and resulted positive in all malignant cases, whereas it was completely absent in benign tumors. On the basis of the obtained results some tumours do not seem to arise from the uterine glands as appears from the negativity to CK19, but from the luminal epithelium. Hormonal therapy of uterine carcinomas in rabbits can be considered more appropriate than the antiblastic therapy, considering the low proliferative activity of endometrial malignant tumors. The low expression of telomerase in adenomas and its absence in adenocarcinomas does not support the importance of telomerase dependence of malignant transformation and the employment of anti-telomerase therapeutic approaches.
2008
26th Annual Meeting: programme and book of abstracts.
50
50
VINCI A.; BACCI B.; BENAZZI C.; SARLI G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/67831
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