2 September 2008
A characteristic pattern of gene expression was associated with the young breast cancer patients. This was not a pattern of specific individual genes, but rather groups of genes sharing similar functions such as cellular signalling and survival. These tumours also showed a different pattern of cell-surface receptors; for example, showing lower expression of the estrogen receptor (ER) but higher levels of the human epidermal growth factor receptor 2 (HER-2) than tumours in the older age-group. The authors propose that their results indicate that breast cancer in some young women may be biologically distinct from other breast tumours, arising from different oncogenic pathways and being characterised by a decreased sensitivity to hormones, and a poorer prognosis. They call for further research in order to develop improved preventative and therapeutic options for women with this form of breast tumour.
Senior author Kimberly Blackwell commented: "Clinicians have long noted that the breast cancers we see in women under the age of 45 tend to respond less well to treatment and have higher recurrence rates than the disease we see in older women, particularly those over the age of 65…by understanding this, we may be able to develop better and more targeted therapies to treat these younger women" (see press release).
Comment: Microarray-based analysis has revealed information about many kinds of tumours that suggests that groups of tumours that may appear similar in terms of clinical and histopathological features can have very different genetic signatures, and that these underlying patterns of gene expression can potentially allow more accurate diagnosis, prognosis and management, perhaps even specifically tailored treatments. This paper does no more than open up a possible line of further enquiry; the data is not sufficient to reliably conclude, as the authors suggest, that breast cancer in younger women is a different disease from that seen in older women. A commentary accompanying the report proposes more realistically that: “Ultimately, we may move away from the concept of disease asa discrete entity that is largely comparable across patientsto one in which the unique molecular features of each tumorand the biology of the patient, including pharmacogenomic differences,must be considered to guide a more personalized therapy” [Peppercorn J, Partridge AH (2008) J Clin Oncol. 26(20):3303-5].