Epidemiology of basal-like breast cancer

Abstract

Risk factors for the newly identified "intrinsic" breast cancer subtypes (luminal A, luminal B, basal-like and human epidermal growth factor receptor 2-positive/estrogen receptor-negative) were determined in the Carolina Breast Cancer Study, a population-based, case-control study of African-American and white women. Immunohistochemical markers were used to subtype 1,424 cases of invasive and in situ breast cancer, and case subtypes were compared to 2,022 controls. Luminal A, the most common subtype, exhibited risk factors typically reported for breast cancer in previous studies, including inverse associations for increased parity and younger age at first full-term pregnancy. Basal-like cases exhibited several associations that were opposite to those observed for luminal A, including increased risk for parity and younger age at first term full-term pregnancy. Longer duration breastfeeding, increasing number of children breastfed, and increasing number of months breastfeeding per child were each associated with reduced risk of basal-like breast cancer, but not luminal A. Women with multiple live births who did not breastfeed and women who used medications to suppress lactation were at increased risk of basal-like, but not luminal A, breast cancer. Elevated waist-hip ratio was associated with increased risk of luminal A in postmenopausal women, and increased risk of basal-like breast cancer in pre- and postmenopausal women. The prevalence of basal-like breast cancer was highest among premenopausal African-American women, who also showed the highest prevalence of basal-like risk factors. Among younger African-American women, we estimate that up to 68% of basal-like breast cancer could be prevented by promoting breastfeeding and reducing abdominal adiposity.

p53 Expression in Triple Negative Breast Carcinomas: Evidence of Age-Related and Racial Differences

“…Results from our cohort also showed that the basal phenotype/p53 positive TNBC is more common in African Americans compared to Caucasians. Our results are consistent with the Carolina Breast Cancer study and others [4,15,17,18]. Awareness of these associations between intrinsic biologic differences and different tumor phenotypes, as well as the prevalence of different tumor phenotypes in different ethnic groups is becoming more important for successful application of individualized targeted therapies.…”

Basal/HER2 breast carcinomas

“…Therefore, at least two types of HER2 gene-amplified breast carcinomas exist (ER-positive and ER-negative). Because several risk factors for developing basal-like breast cancer have been identified (e.g., BRCA1 mutations carriers and young African-American women), and there are no known specific risk factors (including no apparent interaction with race or age) for the HER2-enriched subtype, 1,21,22 it appears reasonable to etiologically consider basal-like and HER2-enriched breast carcinomas as two different breast cancer diseases. 23 Moreover, the basal-like breast cancer subtype displays an obvious and strong common biology, whereas the HER2-enriched subtype solely describes the occurrence of a high but imperfect correlation with HER2 gene-amplification status.…”

Características clínicas y pronosticas de los subtipos moleculares de cáncer de mama determinados por Inmunohistoquímica. Arequipa, Perú

“…estrógeno (RE), receptores de progesterona (RP), HER 2, Ki67, citoqueratinas de alto peso molecular 5 y 6 (CK5/6), citoqueratinas de bajo peso molecular 8 y 18 (CK 8/18), y receptor para el factor de crecimiento epidérmico (EGFR), es posible catalogar los carcinomas de mama en subtipos equivalentes a los determinados por expresión génica (7,8,9) . El objetivo del presente estudio es clasificar los carcinomas de mama en subtipos moleculares mediante la aplicación de marcadores de inmunohistoquímica, así como determinar las características clínicas, patológicas, y pronósticas de sobrevida global en los diferentes fenotipos moleculares.…”