Breast cancer biomarkers aid detection

TriPath Imaging has said that data generated from in-house research studies of the company's proprietary breast cancer biomarkers demonstrate a strong correlation between biomarker expression and recurrence of breast cancer in archived breast tissue samples from a retrospective cohort of patients with early stage breast cancer.

The results of in-house research studies were based on analysis of 427 archived tissue samples collected from a multi-site, retrospective cohort of patients with early stage breast cancer in which 30% suffered recurrence of breast cancer within 10 years of initial diagnosis. For the purposes of these research studies, five biomarkers were incorporated into a proprietary, reproducible, easy-to-use, research assay that involves the staining of tissue biopsies on glass microscope slides.

These biomarkers, selected after an exhaustive discovery and validation process conducted over the past four years, were designed to detect the over-expression of unique cellular proteins that are predictive of breast cancer recurrence. In the research study, tissue section slides prepared from archived breast tissue were stained with each of the five biomarkers allowing for evaluation of each biomarker individually and as a panel of biomarkers by evaluating the combined results of two or more of the tissue section slides. Biomarker staining was analysed using a prototype of TriPath's interactive histology imaging system.

While expression of each individual biomarker correlated with cancer recurrence, the strength of correlation was significantly improved when the analysis included the combined results of a panel of two or more biomarkers. The rate of breast cancer recurrence was directly related to the number of biomarkers that stained positive. When no biomarkers were positive, the cancer recurrence rate was less than 20%. However, the recurrence rate increased to 35% when one biomarker was positive, 65% when 2 biomarkers were positive and nearly 80% with 3 or more positive biomarkers. Furthermore, these results were independent of other known prognostic indicators such as tumour size and HER-2/neu status.

'The prognostic tools available to physicians in breast cancer today are limited to clinical signs such as tumour size and number of lymph nodes involved. However, many women diagnosed early with small tumours and no sign of cancer in the lymph nodes go on to develop cancer recurrence within 5 to 10 years. We targeted our discovery process to find biomarkers that would help the physician identify those women who have the highest likelihood of cancer recurrence and, therefore, may potentially benefit from more aggressive therapy,' said Dr Doug Malinowski, chief scientific officer, TriPath Imaging. 'We believe that the results generated from these retrospective research studies provide an early indication of the validity of our discovery process and philosophy.'