Is Oncotype testing useful in variant histologies such as micropapillary breast cancer?  

I have no idea whether Oncotype testing is predictive of benefit to chemotherapy in micropapillary breast cancer, which is a rare variant. Micropapillary variant tends to worse prognosis and greater degree of nodal positivity in some studies. However, in other studies, the prognosis is similar to in...

Agree with Dr. @Charles L. Shapiro. There is a SEER based Oncotype score study (using preTAILORx cutoffs) by Wang et al., PMID 30619463 that included about 270 micropapillary cases along with IDC, ILC, and other special subtypes like mucinous and tubular. The micropapillary cases had similar percent...