POLE -mutated clear cell cervical cancer associated with in-utero diethylstilbestrol exposure.

We report an extraordinary case of a woman, exposed to diethylstilbestrol in utero, who developed clear cell adenocarcinoma of the cervix with a concurrent polymerase-Ɛ ( POLE ) somatic mutation. The tumor exhibited the classic phenotypic characteristics of POLE -mutated tumors originating from other organs (e.g. the uterus or the colon) including increased tumor infiltrating lymphocytes and high PD-L1 expression and has remained in remission since completion of primary therapy for >4 years. This case highlights the importance of next generation sequencing in unraveling the biology of rare tumors and supports that the presence of a POLE mutation and the associated ultramutated state confers a unique phenotype of higher immunogenicity and possibly improved prognosis in a tissue-agnostic manner, i.e. regardless of the type of cancer where the POLE mutation is present.