Aims: To understand the correlation between the expression status of different biological markers in breast cancers in the elderly.
Methods and results: Three hundred and ninety-seven cases were evaluated for expression of hormone receptors [oestrogen receptors (ER) alpha and beta, progesterone receptor (PR)], basal markers [p63, cytokeratin (CK) 5/6 and CK14] and others (HER2/neu, synaptophysin and chromogranin). The expression rates were 60, 29, 25, 6, 14, 8, 28, 17 and 5%, respectively, for these markers. The expression of ER alpha and beta, PR, synaptophysin and chromogranin at any level correlated with low nuclear or tumour grades, whereas the expression of HER2/neu, CK5/6 and CK14 at any level correlated with high nuclear grade. By using hierarchical clustering, groups of HER2, luminal and basal types were identified. In addition, a neuroendocrine group was also identified, being characterized by expression of synaptophysin, chromogranin, ER and PR, but not HER2/neu, and other basal cytokeratins. This group was associated with lower nuclear grade, and hence better prognosis.
Conclusions: Breast cancer in the elderly shows similar molecular groupings as other breast cancers, with an additional neuroendocrine group that is associated with a favourable biological marker profile.