ARRB1 and neoplasm: Consistent with other studies, our results emphasise the high sensitivity and low specificity of KRT7 for ADC, and confirm the high specificity of TTF1 and NAPSA but their suboptimal sensitivity for ADC, mainly in poorly differentiated tumours.8,21,22 Interestingly, beta-arrestin-1 appeared highly sensitive and specific for ADC in the in-house TMA even in poorly differentiated cases.