James Hsieh, MD, PhD
This is the first of a two-part series on reclassification of renal cell carcinomas (RCCs), many of which are con- sidered non-clear cell RCC (nccRCC). The first part will
outline most clinically relevant classifications that should be taken into consideration in treatment planning, and the sec- ond part will detail the contemporary genomics information on individual subtypes of kidney cancer. With the evolution of RCC classification, some tumors have an atypical morphology and these tumors often are difficult to categorize in any specific subtype. This report highlights these issues, focuses on how the field is evolving, and what factors need to be considered as part of identifying and characterizing new subtypes. Most impor- tantly, the information emerging from new reports not only crystallizes our understanding of pathologic variants but points toward therapeutic and prognostic opportunities as well.