p16 promoter methylation, expression, and its association with estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 subtype of breast carcinoma
Aditi Goyal1, Ram Krishna Sahu2, Mohit Kumar1, Sonal Sharma1, Shariq Qayyum2, Navneet Kaur3, Usha Rani Singh1, Ravi Mehrotra4, Suresh Hedau2
1 Department of Pathology, UCMS and GTB Hospital, University of Delhi, Delhi, India
2 Division of Molecular Oncology, National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh, India
3 Department of Surgery, UCMS and GTB Hospital, University of Delhi, Delhi, India
4 Division of Molecular Cytology, National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh, India
Division of Molecular Oncology, National Institute of Cancer Prevention and Research, I - 7, Sector - 39, Noida - 201 301, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Objectives: The purpose of the study is to investigate p16 protein expression and promoter methylation of p16 gene and their association with molecular subtypes based on parameter such as estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2).
Materials and Methods: A total of 114 breast cancer tissue biopsies were collected for methylation-specific polymerase chain reaction (MSP) and immunohistochemical (IHC) analysis.
Results: Seven tissue microarrays were constructed. p16 protein expression was studied in 114 cases, of which 35/114 (30.7%) cases showed strong expression and the majority of them had ER-positive tumor (57.6%), and it was statistically significant (P < 0.0074). Similarly, p16 expression was reduced in the majority of PR-negative tumors (83.9%) and the association was statistically significant (P = 0.0026). p16 methylation was studied in 114 cases and was positive in 71.0% cases.
Conclusion: High p16 protein expression was associated with ER-positive, PR-negative, and HER2-negative tumors which is associated with poor prognosis. p16 protein expression may be used as a prognostic indicator to predict treatment response to hormonal therapy.