EXPRESSION OF CYCLIN D1 IN NORMAL, HYPERPLASTIC AND NEOPLASTIC ENDOMETRIUM

Background: Overexpression of Cyclin D1, a positive cell cycle regulator, may lead to uncontrolled cell proliferation. Aim: The present study was undertaken to examine the expression profile of Cyclin D1 in normal, hyperplastic and neoplastic endometrium and to evaluate the possibility of its role in the genesis of endometrial neoplastic and preneoplastic lesions. Settings and Design: A cross sectional study conducted during a 1 year period in a tertiary referral centre. Materials and Methods: We evaluated and compared the expression profile of Cyclin D1 in 50 endometrial samplings that were diagnosed as simple hyperplasia without atypia (n=12), complex hyperplasia without atypia (n=7), complex hyperplasia with atypia (n=4), endometrial carcinoma (n=7) and proliferative (n=10) and secretory (n=10) endometrium. Results: An increasing gradient of Cyclin D1 expression was noted in endometrial glands from normal endometrium to hyperplasia to carcinoma Conclusion: Cyclin D1 overexpression is an early event in endometrial carcinogenesis.


INTRODUCTION
Endometrial carcinoma is one of the most common malignancies of female genital tract. 1 accounting for 7 % of all invasive cancers in women. Studies have shown that unopposed estrogen intake exceeding two years has a two to three fold greater risk of endometrial cancer. Clinicopathologic studies and molecular analysis support the classification of endometrial carcinoma into two broad categories referred to as Type 1 and Type 2 endometrial carcinoma. Type 1 carcinoma / Endometrioid carcinoma is the most common type accounting for approximately 80 % of cases. It typically arises in the setting of endometrial hyperplasia and is seen in 55-65 years age group. Type II /Serous Carcinoma occurs in women who are about a decade older than those with Type I carcinoma and does not arise in the background of estrogen overexposure.
Cyclin D1 (also known as BCL1) is a proto-oncogene located on chromosome 11q13. D-cyclins selectively control cell-cycle progression by activating their cdk partners, cdk4 and cdk6, which phosphorylate retinoblastoma (RB) protein that leads to the release of associated proteins like E2F. These proteins have the capability to activate genes necessary for cell progression into the S-phase through G1-phase. 2 Cyclin D1 is often over expressed in human neoplasia e.g. in situ and infiltrating ductal breast carcinoma, colorectal carcinoma, bladder carcinoma, head and neck, lung and prostate cancers. 3  then taking the ratio of immunoreactive nuclei to total number of nuclei multiplied by 100 and rounded off to the nearest 10%. <10% staining was considered as negative for Cyclin D1.11-30% cell positivity was scored 1 +;31-60% positivity was scored 2 + and >60 % positive cells was labelled 3 +. 5

RESULTS
Demographics: In our study, 50 patients were selected in the age group of 26 to 75 years. The 12 patients diagnosed with simple hyperplasia without atypia had an age range of 33 to 64 years with mean age of 43.50±8.74 years and a maximum numbers of 5 cases (45.83%) were in the age group of 41-45 years. The 7 patients diagnosed with complex hyperplasia without atypia had an age range of 38-65 years with mean age of 47.14±10.35years and a maximum number of 3 cases (30%) were in the age group of 36-40 years. The 4 patients diagnosed with complex hyperplasia with atypia had an age range of 31-73 years with mean age of 50.50±19.07years. The 7 patients diagnosed with endometrial carcinoma had an age range of 38-65 years with mean age of 51.86±10.32years and a maximum number of 2 cases (28.57%) were in the age group of 61-65 years.
Rest of the 6 cases (60%) were negative. 6 out of the 12 cases (50%) of simple hyperplasia without atypia showed positivity with an extent of 11-30% and remaining 6 cases (50%) were negative. 3 out of the 7 cases (42.86%) of complex hyperplasia without atypia showed Cyclin D1 positivity with an extent of 11-30% and remaining 4 cases (57.14%) were negative. All 4 cases (100%) of complex hyperplasia with atypia were positive for Cyclin D1 with 11-30% and 31-60% as extent of positivity in 2 cases each. Thus, overall, 63.63% of all the cases of complex hyperplasia showed positivity for Cyclin D1. 6 out of the 7 cases (85.71%) of endometrial carcinoma were found to be positive for Cyclin D1amongst which 4 cases (57.13%) showed an extent of 31-60%, 1 case (14.28%) showed an extent of 11-30% and another case (14.28%) showed an extent of >60%.
Comparison of extent of Cyclin D1: Table 2 shows the comparison of expression profile of Cyclin D1 in paired groups. A statistically significant difference was observed between the results of proliferative phase vs. complex hyperplasia without atypia (p=0.017), proliferative phase vs. complex hyperplasia with atypia (p= 0.014), proliferative phase vs. endometrial carcinoma (p = 0.021), secretory phase vs. complex hyperplasia without atypia (p =0.020), secretory phase vs. complex hyperplasia with atypia (p =0.039), secretory phase vs. endometrial carcinoma (p =0.036), simple hyperplasia without atypia vs. complex hyperplasia without atypia (p = 0.039), simple hyperplasia without atypia vs.

DISCUSSION
Over expression of cyclin D1 may be associated with actual gene amplification or transcriptional dysregulation in cancers. We have used immunohistochemistry to demonstrate that cyclin D1 is overexpressed in hyperplastic lesions, which are considered to be the precursors of endometrioid adenocarcinoma.
In the current study, cyclin D1 expression is negative in 70% of proliferative endometrium and positive in 30% of proliferative endometrium. In secretory phase cyclin D1 is positive in 40% of cases and negative in 60% of cases. Difference between the expression of cyclin D1 in proliferative and secretory phase is statistically insignificant.
In previous studies, the positivity of Cyclin D1 ranges from 0 % to 36 % in normal endometrium.In a study by M Ruhul Quddus et al 6 , cyclin D1 expression in proliferative endometrium is 36% positive and remaining 64% is negative. In secretory phase, 34% is positive and 66% is negative. This study correlates well with our study. In a study by Sema Ozuysal et al 7   Vijay Suri., Shaffy and Karishma Sharma., Expression of Cyclin D1 In Normal, Hyperplastic And Neoplastic Endometrium expression of cyclin D1 may be associated with actual gene amplification or transcriptional dysregulation in cancers. We have used immunohistochemistry to demonstrate that cyclin D1 is overexpressed in hyperplastic lesions, which are recursors of endometrioid In the current study, cyclin D1 expression is negative in 70% of proliferative endometrium and positive in 30% of proliferative endometrium. In secretory phase cyclin D1 is positive in 40% n 60% of cases. Difference between the expression of cyclin D1 in proliferative and secretory phase is In previous studies, the positivity of Cyclin D1 ranges from 0 % to 36 % in normal endometrium.In a study by M Ruhul , cyclin D1 expression in proliferative endometrium is 36% positive and remaining 64% is negative. In secretory phase, 34% is positive and 66% is negative. This study correlates well with our study. In a study by Sema % cases of proliferative endometrium are positive. This study shows very low positivity when compared with our results. Nishimura et al 2 (2004) reported no expression in the secretory phase and focal staining In our study, expression of Cyclin D1 in simple hyperplasia (50%), in complex hyperplasia without atypia (42.86%), in complex hyperplasia with atypia (100%), overall in complex hyperplasia (63.63%) and in endometrial carcinoma (85.7 %) has the closest resemblance with the resul by Quddus et al. 6 Quddus et al 57% in simple, 71% in complex hyperplasia and 68% in endometrial carcinoma. In our case, the positivity for complex hyperplasia was less than the positivity for carcinoma endometrium.
In previous studies, the positivity of Cyclin D1 in endometrial hyperplasia ranges from no positivity as reported by Tsuda al 8 to 83% reported by Cao role of Cyclin D1 in the development of endometrial carcinoma. He found that Cyclin D1 expression was limited to only few cells of hyperplastic endometrium, whereas 40% of endometrioid carcinoma showed Cyclin D1 expression. Nishimura et al 2 found 25% positivity in endometrial hyperplasias and 46.1% in endome Based on current study, overexpression of cyclin D1 increases from normal endometrium to hyperplasia and carcinoma, suggesting that it may play a role in endometrial carcinogenesis. cancer.
Our findings support the significance of co as a precursor lesion and to some extent simple hyperplasia is also precancerous. The mechanism of dysregulation of Cyclin D1 in endometrial neoplasia is not clearly defined, but it is likely that dysregulation plays an important role in the proportion of cells in transition from G1 to S phase.

CONCLUSION
Cyclin D1 expression in endometrial glands increases progressively in extent from normal endometrium to hyperplasia to carcinoma. It appears that the dysregulation is maximal at the complex hyperplasia state and that cyclin D1 overexpression may be an early event in endometrial carcinogenesis. Our findings support the significance of complex hyperplasia as a premalignant lesion. Intensity and extent of Cyclin D1 expression on should be used as an adjuvant to histopathological diagnosis for the cases of complex hyperplasia with high malignant potential for the benefit of patients. on of Cyclin D1 in simple hyperplasia (50%), in complex hyperplasia without atypia (42.86%), in complex hyperplasia with atypia (100%), overall in complex hyperplasia (63.63%) and in endometrial carcinoma (85.7 %) has the closest resemblance with the results in the study done et al reported Cyclin D1 positivity as 57% in simple, 71% in complex hyperplasia and 68% in endometrial carcinoma. In our case, the positivity for complex hyperplasia was less than the positivity for carcinoma In previous studies, the positivity of Cyclin D1 in endometrial hyperplasia ranges from no positivity as reported by Tsuda et to 83% reported by Cao et al. 9 Nikaido et al 4 studied the role of Cyclin D1 in the development of endometrial arcinoma. He found that Cyclin D1 expression was limited to only few cells of hyperplastic endometrium, whereas 40% of endometrioid carcinoma showed Cyclin D1 expression. found 25% positivity in endometrial hyperplasias and 46.1% in endometrioid carcinomas.
Based on current study, overexpression of cyclin D1 increases from normal endometrium to hyperplasia and carcinoma, suggesting that it may play a role in endometrial Our findings support the significance of complex hyperplasia as a precursor lesion and to some extent simple hyperplasia is also precancerous. The mechanism of dysregulation of Cyclin D1 in endometrial neoplasia is not clearly defined, but it is likely that dysregulation plays an important role in increasing the proportion of cells in transition from G1 to S phase.
Cyclin D1 expression in endometrial glands increases progressively in extent from normal endometrium to hyperplasia to carcinoma. It appears that the dysregulation is at the complex hyperplasia state and that cyclin D1 overexpression may be an early event in endometrial carcinogenesis. Our findings support the significance of complex hyperplasia as a premalignant lesion. Intensity and extent of Cyclin D1 expression on immunohistochemistry should be used as an adjuvant to histopathological diagnosis for the cases of complex hyperplasia with high malignant potential ssion of cyclin D1 and p53 protein in human uterine endometrial carcinomas. Cancer,