TACSTD2 and neoplasm: Consistent with the data above, we found that, compared with that in the non-cancerous prostate gland (‘normal’) samples, the expression of the GSE1 protein increased with the tumor grade, with the strongest immunoreactivity in patients with medium- and high-grade PCa; conversely, TACSTD2 expression was the highest in the ‘normal’ prostate samples and barely expressed in patients with high-grade PCa (Figure 6A).