Furthermore, the proportion of patients with elevated HER2 ECD levels increased with more advanced and aggressive tumors: 11.3% of those at stage III, 9.3% of those with negative hormone-receptor status, 6.9% of those with high-grade disease, 6.4% of those with positive LN metastasis, and 6.3% of those with a tumor size of >2 cm. The gene discussed is ERBB2; the disease is neoplasm.