ESR1 and neoplasm: Looking beyond the HER2 oncoprotein, we are interested in scrutinizing the truncated estrogen receptor isoform (ERα36) in tumor progression and metastasis of triple negative breast cancer,44 the BAG-1 isoforms in tumorigenesis and chemoresistance,45 and a new Bruton’s tyrosine kinase isoform (p65BTK) found in colon cancer.46 While both alternative translation at internal ribosome entry sites, IRES47,48 and shedding/activation of oncoproteins49,50 have received increased attention in tumorigenesis, selective measurement tools are needed to advance understanding in these areas.