More recently, the heterogeneity of cancer- and immune-related proteins was compared in pre-treatment and on-treatment biopsy samples from HER2-positive cancers undergoing neoadjuvant HER2-targeting treatment, which revealed that the increased heterogeneity of immune-related proteins (e.g., pan-leukocyte marker CD45) after a single cycle of HER2-targeting agents was associated with a complete response [68]. The gene discussed is ERBB2; the disease is cancer.