Introduction: Breast cancer is the leading oncogenic threat in South-East Asian women showing an inexplicable biological aggressiveness. High expression of cyclin D1, a key molecule in breast cancer pathogenesis, has been shown by previous studies in the Western world to be associated with favorable tumoral characteristics. Apart from determining the correlation between cyclin D1 expression and standard clinicopathological variables in invasive breast cancer in Eastern India, questions that we aimed to answer through this study included: Is there a significant regional difference in expression patterns of this protein? And if yes, can it possibly account for the epidemiological differences in breast cancer occurrence and biological behavior? Finally, is testing for overexpression of this protein in regions with limited resources beneficial?
Materials and methods: The present study was carried out on 110 previously untreated, female patients with primary breast carcinoma. Cyclin D1 expression was determined by immunohistochemistry using specific anti-cyclin D1 monoclonal antibodies.
Results: Overexpression of cyclin Dl was found in 78 of 110 cases (70.9%). High expression of cyclin D1 showed a significant negative correlation with tumor size (P = 0.023) and tumor grade (P = 0.045). Estrogen receptor and progesterone receptor positive cases showed a significantly positive correlation with cyclin D1 overexpression (P = 0.026 and 0.046, respectively). Interestingly, cyclin D1 positivity showed a strong correlation with the type of surgical procedure performed (P = 0.002).
Conclusion: Cyclin D1 overexpression in breast cancer is associated with less aggressive tumoral characteristics. Furthermore, its potential epidemiological role and utility as a prognostic marker have been discussed.
Keywords: Breast cancer; cyclin D1; immunohistochemistry; prognostic factor.