Two proteins highly associated with the spread of breast cancer into neighboring lymph nodes have been detected. Although yet unidentified, scientists speculate that these proteins are thymosin beta-10, a peptide that has already been associated with out-of-control growth and cell differentiation, and an ubiquitin protein associated with a good prognosis in node-negative breast cancer.

Two protein peaks associated with lymph node metastasis were identified. Specifically, over-expression of protein peaks at 4,871 Da (which represents the molecular weight of the protein) and under-expression of a protein peak at 8,596 Da were highly predictive of lymph node metastasis.

Patients with two or more positive lymph nodes were significantly more likely to show over-production of 4,871 Da, compared to patients with no lymph node spread. The peak at 4,871 could also predict patients with four or more metastatic nodes who have significantly worse outcomes.

Scientists say further tests will have to confirm the identities of these proteins, but these may have potentials for use as prognostic biomarkers for breast cancer metastasis.