Molecular Breast Cancer Subtypes in Premenopausal and Postmenopausal African-American Women: Age-Specific Prevalence and Survival

• Published in: The Journal of surgical research Vol. 143; no. 1; pp. 109 - 118
• Main Authors: Ihemelandu, Chukwuemeka U., M.D, Leffall, LaSalle D., M.D, Dewitty, Robert L., M.D, Naab, Tammey J., M.D, Mezghebe, Haile M., M.D, Makambi, Kepher H., Ph.D, Adams-Campbell, Lucile, Ph.D, Frederick, Wayne A., M.D
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY Elsevier Inc 01.11.2007; Elsevier
• Subjects: Adult; African Americans; African-American women; Age Factors; Aged; Aged, 80 and over; Biological and medical sciences; Breast Neoplasms - ethnology; Breast Neoplasms - genetics; Breast Neoplasms - pathology; Female; Gene Expression Regulation, Neoplastic; General aspects; Gynecology. Andrology. Obstetrics; Humans; Kaplan-Meier Estimate; Mammary gland diseases; Medical sciences; Middle Aged; molecular breast cancer subtypes; postmenopausal; Postmenopause; premenopausal; Premenopause; Prevalence; Prognosis; Receptor, ErbB-2 - genetics; Receptor, ErbB-2 - metabolism; Receptors, Estrogen - genetics; Receptors, Estrogen - metabolism; Receptors, Progesterone - genetics; Receptors, Progesterone - metabolism; Retrospective Studies; Surgery; Tumors; premenopausal; molecular breast cancer subtypes; African-American women; postmenopausal; Human; Prevalence; Premenopause; Breast cancer; Malignant tumor; Epidemiology; Survival; Medicine; Mammary gland diseases; Treatment; Surgery; Postmenopause; Adult; Female; Mammary gland; Woman; Age; African American
• ISSN: 0022-4804; 1095-8673
• DOI: 10.1016/j.jss.2007.03.085

Background Breast cancer is currently regarded as a heterogeneous disease classified into various molecular subtypes using gene expression analysis. These molecular subtypes include: basal cell-like, Her-2/neu, luminal A, and luminal B. Objectives To analyze the prevalence and clinicopathologic associations for molecular breast cancer subtypes in premenopausal and postmenopausal African-American women. Design A retrospective analysis of all African-American women diagnosed with breast cancer from 1998 to 2005, who had assessable data for ER, PR, and Her-2/neu status. Molecular subtype classification was done based on immunohistochemical surrogates for ER, PR, and Her-2/neu status obtained from Howard University tumor registry for each patient. The molecular subtypes were defined as: luminal A (ER+ and/or PR+, HER2−), luminal B (ER+ and/or PR+, HER2+), basal-like (ER−, PR−, HER2−), and Her-2/neu (ER−, PR−, and HER2+). Outcome Measures We analyzed the prevalence of molecular breast cancer subtypes in a population of African-American women and determined their associations with patient demographics and clinicopathologic variables: node status, tumor size, histological grade, p53 mutation status, and breast cancer-specific survival. Results The luminal A subtype was the most prevalent in our study sample (55.4%) compared with (11.8%) luminal B, (21.2%) basal cell-like, and (11.6%) Her-2/neu subtypes. The molecular subtypes did not differ by menopausal status. However, when stratified into age-specific groups, the basal cell-like subtype (57.1%) was the most prevalent in the age group <35 y compared with luminal A, luminal B, and Her-2/neu subtypes at 25.0%, 14.3%, and 3.6%, respectively. The basal cell-like subtype also showed an age-specific bimodal distribution with a peak in the <35 y and 51 to 65 y age groups. The basal cell-like and the Her-2/neu subtypes showed an increased association with clinicopathologic variables portending a more aggressive clinical course when compared with luminal A subtype. A paradoxical inverse relationship between the expression of p53 and Bcl-2 protooncoprotein was noted in the molecular subtypes. Breast cancer-specific survival differed significantly among the molecular subtypes ( P < 0.04), with the basal cell-like and Her-2/neu subtypes having the poorest outcome. Conclusions The high prevalence of the basal cell-like subtype in the young premenopausal African-American women aged <35 y could be a contributory factor to the poorer prognosis of breast cancer observed in this cohort of patients.