Utilizing Advanced Molecular Analysis to Tailor Treatment for Cancer of Unknown Primary Site: A Case Report and Lecture Review

Abstract

Abstract Cancer of unknown primary site (CUP) presents as metastatic lesions without an identified primary tumor despite extensive evaluation. Because the primary cancer type cannot be determined, there are no standard treatments, leading to challenges in the treatment and suboptimal clinical outcomes. Herein, we report a 59-year-old woman who presented with an enlarged right inguinal lymph node, and the biopsy revealed metastatic adenocarcinoma. Despite a series of treatments including surgery, radiotherapy, and chemotherapy, the disease progressed. After further treatment with combined chemotherapy and immunotherapy, a treatment response was observed. Genomic profiling was done, which identified KRAS G13D and PIK3CA H1047R mutations. She received treatment with the mTOR inhibitor everolimus, and after 2 months, the right inguinal mass continued to regress. This case highlights that CUP remains a diagnostic and therapeutic challenge, representing an urgent and unmet clinical need. However, in the era of precision medicine, the combination of advanced molecular profiling and sophisticated bioinformatic analysis may have the potential to identify druggable targets for tailored and personalized treatment approaches.