A study by Seijnhaeve et al. compared SYP and CgA with INSM1 by using a validation cohort of 22 mammary neoplasms (8 solid papillary carcinomas, 6 mucinous carcinomas, 3 invasive carcinomas, 3 encapsulated papillary carcinomas (SPC), and 2 spindle cell variants of ductal carcinoma in situ cases) with or without neuroendocrine differentiation. Here, SYP is linked to mucinous adenocarcinoma.