ERBB2 and breast cancer: Another recent study introduced a customized ViT algorithm, which can effectively stage HER2 expression in breast cancer using H&E stained images, outperforming conventional models and significantly reducing the need for expensive and complex immunohistochemical staining, thus enhancing diagnostic accessibility in low-resource settings [17].On the other hand, while MIL (Multiple Instance Learning) remains a widely used and resource-efficient method for WSI analysis, we opted for a block-based ViT (Vision Transformer) approach for several reasons.