Immunohistochemical expression of Retinoblastoma gene product in
normal, hyperplastic and malignant endometrium. Correlation with p53 protein
expression, c-erbB-2, hormone receptors' status and proliferative
activity
Affiliations: Dept. of Pathology, Medical School, University of
Ioannina, Ioannina, Greece | Dept. of Pathology, General Hospital of `G.
Hatzikosta', Ioannina, Greece | Dept. of Experimental Physiology, Medical School,
University of Ioannina, Ioannina, Greece
Note: [] Address for correspondence: Dr Elli Ioachim, Department of
Pathology, Medical School, University of Ioannina, 45110 Ioannina, Greece.
Tel./Fax: +30 651 99212; E-mail: ioachime@otenet.gr
Abstract: Alterations of the retinoblastoma (Rb) gene have been described in
several human neoplasms and recently, it has been suggested that these
alterations may play a role in the development of endometrial carcinomas.
Paraffin sections from 31 cases of normal endometrium (16 proliferative, 15
secretory), 35 hyperplastic lesions and 89 endometrial carcinomas were
investigated immunohistochemically for Rb protein (pRb) expression. The results
were compared with p53 and c-erbB-2 protein expression, estrogen (ER) and
progesterone (PR) receptors' status and with clinicopathological prognostic
factors. pRb was expressed in normal, hyperplastic and neoplastic epithelium.
Proliferative endometrium showed more intense and extensive pRb staining than
secretory endometrium. pRb reactivity was heterogeneous in the hyperplastic
endometrial cells. Lack or focal (< 10% endometrial cells) pRb
immunostaining was noted in 56.2% carcinomas, respectively. In the remaining
cases (16.8%) staining was heterogeneous or diffuse. The absence or presence of
pRb expression was independent of grade and stage. In normal proliferative and
secretory endometrium, pRb expression was correlated with PR (p=0.006 and
p=0.001, respectively), PCNA (p=0.04 and p=0.01, respectively) and MIB1 (p=0.02
and p<0.0001, respectively) expression. In hyperplasias, pRb was related to
PR (p=0.016) and MIB1 (p<0.0001) expression. In carcinomas, a relationship
of pRb expression with p53 (p=0.0015), ER (p=0.0002), PR (p=0.0004) and PCNA
(p=0.013) status was detected. We suggest that the absence or presence of pRb
expression does not seem to be associated with the progression of endometrioid
carcinoma. In addition, pRb seems to be normally regulated in relation to the
proliferative growth fraction of the tumours.
