BC type changes based on treatment

Maybe treatment impacts BC phenotype more than we think.

Two studies that indicate treatment can cause hormone receptors and HER2+ expression to change, sometimes for the better, sometimes for the worse. The first also says the supplement sulforaphane may be effective in blocking cell proliferation in triple negative BC. (That study is from the University of Michigan, where they have done a lot of research on sulforaphane).

Trastuzumab resistance induces EMT to transform HER2⁺ PTEN⁻ to a triple negative breast cancer that requires unique treatment options

"Furthermore, these transformed trastuzumab resistant cells exhibit increased BCSC populations and rate of metastasis."

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC462913...

Impact of Molecular Subtype Conversion of Breast Cancers after Neoadjuvant Chemotherapy on Clinical Outcome

"HR+/HER2– tumors tended to convert into triple negative (TN) tumors (10.3%), whereas 34.6% of TN tumors gained HR positivity to become HR+/HER2– tumors. Clinical outcomes of molecular subtype conversion groups were compared against patients who remained as HR+/HER2– throughout. The HR+/HER2– to TN group had significantly poorer recurrence-free survival (RFS) (hazard ratio, 3.54; 95% confidence interval [CI], 1.60 to 7.85) and overall survival (OS) (hazard ratio, 3.73; 95% CI, 1.34 to 10.38). Patients who remained TN throughout had the worst outcomes (for RFS: hazard ratio, 3.70; 95% CI, 1.86 to 7.36; for OS: hazard ratio, 5.85; 95% CI, 2.53 to 13.51), while those who converted from TN to HR+/HER2–showed improved comparable survival outcomes."

http://e-crt.org/journal/view.php?doi=10.4143/crt.2014.262