Cancer in multi-lineage mosaic RASopathies due to pathogenic variants in HRAS or KRAS: a systematic review and meta-analysis

Purpose: To determine the cancer risk and spectrum in patients with multi-lineage mosaic RASopathies with pathogenic variants (PV) in HRAS or KRAS. Methods: We conducted a systematic literature review to identify multi-lineage mosaic RASopathy cases with a PV in HRAS or KRAS to create a retrospective cohort. We calculated cumulative incidence, cancer-free survival and hazard rates (HR) for cancer and standardized incidence rates (SIR). Results: This study identified 69 patients. Seventeen percent had cancer, including rhabdomyosarcoma located in the urogenital region (n=7), skin cancer (n=3), Wilms tumor (n=1), and bladder cancer (n=1). Cumulative cancer incidence by age 20 was 20% (95% CI, 4 to 37%). The annual cancer HR peaked at 14% within the first two years of life. The highest SIR was found for rhabdomyosarcoma (SIR = 800, 95% CI, 300 to 1648). Conclusions: This is the first investigation of cancer risk in KRAS or HRAS PV-positive mosaic RASopathies to date. The high incidence and SIR values found highlight the need for rigorous rhabdomyosarcoma surveillance in young children and skin cancer surveillance in adults with this high-risk condition.