Molecularly Defined Renal Carcinomas

Abstract

RCC has witnessed a significant increase in its incidence over the last five decades, ranking as the ninth most common cancer globally. Although survival rates have improved substantially, RCC remains one of the deadliest urological cancers. Traditionally, RCC subtypes were classified based on histopathological features. However, in recent years, there has been a paradigm shift towards molecular and genomic characterization of RCC, leading to the recognition of distinct molecular subtypes. The 2022 World Health Organization (WHO) classification introduced a new category called “molecularly defined renal carcinomas,” encompassing various subtypes, including SMARCB1-deficient medullary carcinoma, ALK-rearranged RCC, FH-deficient RCC, SDH-deficient RCC, ELOC-mutated RCC, TFEB-altered RCC, and TFE3-rearranged RCC. These molecular subgroups have significant consequences for diagnosis, prognosis, and treatment. Molecularly defined RCCs are frequently underrepresented in clinical trials, encouraging additional research to identify beneficial therapeutics. Immune checkpoint inhibitors and tyrosine- kinase inhibitors have shown promising results in some subtypes, while others may benefit from specific inhibitors targeting their molecular drivers. Additionally, these classifications have important prognostic implications, guiding treatment decisions and genetic counseling.