e22019 Background: Conventionals serum biomarkets have a low sensibility in breast cancer diagnosis. Proteomic is a promising tool to identify new proteins profiles to be used in screening and early diagnosed. Methods: 1)Biomarker identification: Serum proteins from 114 women were separated and analysed by bidimensional gel electrophoresis; data from 72 patients (p) were compared with those from 42 control women to search for differentially expressed proteins. Several comparisons were performed between controls and p regarding clinical parameters such as histological type, tumour stage and lymph node affection (-/+). A total of 53 spots were found to be differentially expressed and identified by mass spectrometry (MS) as potential breast cancer biomarkers.2) Protein Chip development: A Protein Chip was developed with antibodies against six biomarkers and three control proteins (an antibody for the detection of a spiked control, for data normalization and two proteins as positive and negative controls). An antibody against CA15–3 antigen was also included as a reference breast tumour marker to be compared with our biomarker panel. 3) Clinical validation of the Protein Chip: A clinical validation study was carried out with 75 healthy women and 125 breast cancer p. After multivariate statistical analysis of the biomarker data, CA15–3 was discarded due to its low significance while a panel of 5 biomarkers was obtained as the best predictive model to discriminate p from healthy subjects. Results: 53 diferentially expressed proteins have been identified as potential breast cancer serum biomarkers after analysing 114 serum samples by 2DE Technology. A Protein Chip has been developed for the simultaneous detection of five serum biomarkers and three control proteins. After clinical validation with 200 p and healthy women, the sensitivity of the Protein Chip to detect breast cancer was 95% and its specificity was 27%. Conclusions: The high sensitivity of the Protein Chip suggests that it could be a valid tool to complement mammography (sensitivity < 80%) in breast cancer screening programs, specially when its sensitivity tends to decrease, as it happens in young women and dense breast cases. Larger clinical validation trials are being developed. This work is supported by INDAS BIOTECH. No significant financial relationships to disclose.
Serum proteins as tumour markers for breast cancer
