Genetic analysis of cervical cancer with lymph node metastasis.

Objective: To find out the differences in gene characteristics between cervical cancer patients with and without lymph node metastasis, and to provide reference for therapy.

Methods: From January 2018 to June 2022, recurrent cervical cancer patients 39 cases with lymph node metastasis and 73 cases without lymph node metastasis underwent testing of 1,021 cancer-related genes by next-generation sequencing. Maftools software was used to analyze somatic single nucleotide/insertion-deletion variation mutation, co-occurring mutation, cosmic mutation characteristics, oncogenic signaling pathways.

Results: EP300 and FBXW7 were significantly enriched in lymph node-positive patients. Lymph node-positive patients with EP300 or FBXW7 mutations had lower overall survival (OS) after recurrence. Both lymph node-positive and -negative patients had plenty of co-occurring mutations but few mutually exclusive mutations. Lymph node-positive co-occurring mutation number ≥6 had lower OS, while lymph node-negative co-occurring mutation number ≥3 had lower OS after recurrence. The etiology of SBS3 was defects in DNA double strand break repair by homologous recombination, which exclusively exist in lymph node-positive patients. There was no difference in median tumor mutation burden (TMB) between positive and negative lymph nodes, but TMB was significantly associated with PIK3CA mutation.

Conclusion: The somatic SNV/Indels of EP300 and FBXW7, SBS3 homologous recombination-mediated DNA repair defect were enriched in lymph node-positive patients. For lymph node-positive patients, EP300 or FBXW7 mutations predicted poor prognosis. No matter lymph node-positive or negative, more co-occurring mutation number predicted poor prognosis. PIK3CA mutation may account for the higher TMB and help identify patients who benefit from immunotherapy.