Abstract
RATIONALE: Blockade of programmed death protein 1 (PD-1), have been observed to have quite good efficacy in recurrent and metastatic cervical cancer. Generally, we believe that the biomarkers of PD-1 inhibitors are programmed cell death-ligand 1, tumor mutational burden, high microsatellite instability, or deficient mismatch repair. However, in the case reported below, we observed that the patient with negative existing predictive biomarkers have significant benefits after zimberelimab monotherapy, indicating that there were other biomarkers that may predict immunotherapy efficacy. However, currently, no one has explored and studied the other potential biomarkers of PD-1 inhibitors. PATIENT CONCERNS: A 51-year-old patient, diagnosed with cervical adenocarcinoma nearly 11 years ago, requested treatment. DIAGNOSES: The next-generation sequencing has shown PIK3CA E545K, SMAD4 1309-1G, and ALK E717K gene mutations, receptor tyrosine kinase 2 (ErbB-2) amplification, microsatellite stability, and low tumor mutational burden of 6.3 mutations per megabase. And immunohistochemistry revealed that the tumor was programmed cell death-ligand 1 negative. INTERVENTION: Zimberelimab monotherapy was accepted as third-line treatment. OUTCOMES: The patient had received zimberelimab for nearly 10 months, the best tumor response was PR (Response Evaluation Criteria in Solid Tumours) and no noticeable adverse reactions were observed. LESSONS: PIK3CA-E542K, ErbB2 amplification, and SMAD4 mutations could be potential biomarkers for PD-1 inhibitors, but a single instance is insufficient to validate the hypotheses. A larger number of patients or more clinical data will be necessary to determine whether these gene mutations are appropriate biomarkers for patients when treatment with PD-1 inhibitors.