Mucinous ovarian neoplasms exhibit a spectrum of differentiation (Table 4) with most tumors (71%) showing gastrointestinal immunophenotype (CLDN18+/CDX2±/ER−), 6% showing pure mullerian differentiation (CLDN18−/CDX2−/ER+) and the remaining cases exhibiting dual gastrointestinal and mullerian differentiation (CLDN18+/CDX2±/ER+) [37]. Here, CLDN18 is linked to ovarian neoplasm.