Biomarker Discordance in Metastatic Bowel Cancer

HER3 expression found in 40% of stage IV SBA tumors.

HER2 positivity noted in 8% of cases.

MMR deficiency identified in 12% of tumors.

Minimal overlap observed among biomarkers.

Variability observed in primary vs metastatic tumors.

MMRd more frequent in stage III compared to stage IV.

Study focused on protein expression, not gene mutations.

HER3 was the most prevalent marker identified in the study.