POU5F1 and salivary gland carcinoma: Unlike previous studies on Nanog, SOX2, OCT4 in salivary carcinomas (Ramachandran et al. 2014; Xu et al. 2017; Nanduri et al. 2013; Li et al. 2014) and POU5F1 (Oliveira Moura et al. 2021; Möller et al. 2008; Antonescu et al. 2011), the consistent immunonegativity observed in this study, along with the absence of molecular alterations in POU5 F1 in MAML2-rearranged MECs, indicates that POU5F1 pseudogenes (e.g., POU5F1B) or splice variants (e.g., POU5 F1- δA) do not contribute to MEC progression.