ERBB2 and diabetes mellitus: Estrogen and progesterone, known to regulate ERBB2 transcription, likely contribute to these differences, with ER-negative tumors exhibiting more aggressive phenotypes.23,24 Additionally, patients with diabetes (66% positivity) and hypertension (37% in first PCR, 100% in nested PCR) displayed elevated ERBB2 expression compared to those without these comorbidities (Table 2).