Retrospective blood test study shows high breast cancer discrimination

A serum assay measuring the BF-09 protein, also known as SAGA-associated factor 29, showed high diagnostic performance for breast cancer in a retrospective feasibility study involving 261 patients and 136 controls. In an independent validation set, the test produced an area under the receiver operating characteristic curve of 0.95, with 93.2% sensitivity and 85% specificity at a cutoff selected in the training data. The study assessed blood samples collected previously, rather than testing asymptomatic participants prospectively during routine breast cancer screening.

Performance in the training set was strong: the area under the curve was 0.92, with a 95% confidence interval of 0.86–0.96, while sensitivity reached 87.3% at 85.7% specificity. The independent validation set yielded an area under the curve of 0.95, with a 95% confidence interval of 0.91–0.97. At the fixed cutoff, sensitivity was 93.2% and specificity was 85%.

The investigators also performed internal validation through bootstrapping and Monte Carlo cross-validation, reporting that the assay’s discriminatory power remained robust under statistical resampling. These subgroup observations were derived from the retrospective study population, and the supplied results do not provide separate performance estimates for each subgroup. The study therefore supports the feasibility of BF-09 as a candidate blood-based marker, but it does not establish performance in a prospective screening population or show that use of the assay improves clinical outcomes.

Mammography is the standard-of-care screening method for breast cancer, although the paper identifies tissue density and overdiagnosis of benign conditions among its limitations and notes growing interest in alternative blood-based tests. Against that background, the findings offer preliminary support for BF-09 as a possible alternative screening assay rather than a validated replacement for established screening. Additional prospective evaluation would be needed to determine how the test performs when used in the intended screening setting.

The authors characterized BF-09 as having high potential as an alternative breast cancer screening test, based on the reported retrospective diagnostic performance and internal statistical validation.

Subject of Research: Retrospective evaluation of serum BF-09 for breast cancer detection.

Article Title: Diagnostic potential of serum BF-09 biomarker (protein SGF29) for early detection of breast cancer: high performance for early-stage cancer and major histological or molecular subtypes

Article References: Chavany, C., Dea, J., Valle, R. P. C., González, R. H., & Jendoubi, M. (2026). Diagnostic potential of serum BF-09 biomarker (protein SGF29) for early detection of breast cancer: high performance for early-stage cancer and major histological or molecular subtypes. Journal of Cancer Research and Clinical Oncology. https://doi.org/10.1007/s00432-026-06634-2

Image Credits: AI Generated

DOI: 10.1007/s00432-026-06634-2

Keywords: breast cancer, BF-09, SGF29, blood biomarker, ELISA, diagnostic accuracy, cancer screening, retrospective study, early detection, mammography, Diagnostic, potential