Molecular Profiles of Brain and Pulmonary Metastatic Disease in Cancer of Unknown Primary.

Cancers of unknown primary (CUP) are histologically confirmed malignancies but for which further investigation cannot identify a primary site. Improvements in histopathologic modalities for diagnosis have lessened the frequency of CUPs to 3%-5% of all malignancies compared with historical estimates of 5%-10%. Despite this, there is an ongoing debate as to whether CUPs are malignancies where the primary is not found or if they are otherwise a fully separate entity. Improvements in molecular analysis holds promise for improved identification and treatment of CUPs with mixed preliminary results. Here we present a woman with CUP and metastases in her brain and lung. We performed genomic profiling to compare the molecular makeup of each site in order to establish treatment targets. KEY POINTS: Cancer of unknown primary remains a diagnostic and therapeutic challenge. Molecular analysis may provide improvements in diagnosis and novel treatment options. Different sites of metastatic disease have subtle variations in molecular profile. Sequencing of different sites may offer therapeutic options that are either already approved or available in clinical trial.