Plus Therapeutics, Inc. (Nasdaq: PSTV) and Genomic Testing Cooperative, LCA announced a collaboration to integrate next-generation sequencing (NGS) technology into the CNSide cerebrospinal fluid (CSF) assay platform, according to a press release issued July 16, 2026.

The collaboration is intended to enable DNA and RNA profiling across hundreds of biomarkers from a single CSF specimen, adding a molecular sequencing layer to CNSide's existing circulating tumor cell (CTC) enumeration capability within one CLIA-accredited platform.

The CNSide CSF Tumor Cell Enumeration test received a dedicated AMA PLA code 0640U, effective July 1, 2026, and the CNSide CLIA laboratory is enrolled with Medicare. Commercial payer agreements covered approximately 126 million U.S. lives as of the company's most recent quarterly update. A health-economic analysis cited by the company associated CNSide-enabled earlier diagnosis of leptomeningeal metastases (LM) with an approximately 40% reduction in overall LM-related healthcare costs.

Leptomeningeal metastases occur in an estimated 5% to 10% of patients with metastatic solid tumors, representing a U.S. addressable population of more than 100,000 patients per year, according to the press release.

Under the arrangement, Genomic Testing Cooperative will provide sequencing and informatics as a technical service input to the CNSide CLIA laboratory. The companies stated the collaboration aligns with updated National Comprehensive Cancer Network CNS Cancers Guidelines (Version 2.2026), which recognize CSF CTCs alongside tumor-derived DNA.

"By adding comprehensive DNA and RNA profiling across hundreds of biomarkers, we expect to generate one of the most complete longitudinal molecular data sets in CNS oncology," said Russell Bradley, President and General Manager of CNSide Diagnostics, LLC.

Maher Albitar, M.D., Chief Executive Officer and Chief Medical Officer of Genomic Testing Cooperative, said the combination of cell-free DNA and RNA testing with CNSide CTC enumeration "provides the most comprehensive evaluation of CSF."

The NGS-enabled expanded CNSide menu is not yet commercially available. CNSide is a laboratory developed test and has not been cleared or approved by the FDA.