Renal Tumors

Renal rhabdomyosarcoma is a highly malignant tumor that usually occurs in children up to 2 years of age and belongs to the same tumor spectrum as atypical teratoma-like rhabdomyosarcoma of the central nervous system. Its most characteristic molecular pathological alteration is the double allele inactivation/deletion of SMARCB1(INI1) located on chromosome 22 (approximately 80%), resulting in a lack of SMARCB1IHC expression. The same alteration was also seen in extra-renal rhabdomyosarcoma, renal medullary carcinoma, soft tissue epithelioid sarcoma, epithelioid malignant peripheral nerve sheath tumor (50%) and some myoepithelial carcinomas. This probe contains a 22-gauge long arm internal control probe for use as an aid in the diagnosis of tumors associated with SMARCB1 gene deletion.

Other Soft Tissue Tumors

SMARCB1(INI1) deletion can occur in malignant rhabdomyosarcoma, epithelioid sarcoma, epithelioid malignant peripheral nerve sheath neoplasms (50%), and some myoepithelial carcinomas.

Tumors of the Central Nervous System

Tumors of embryonic origin other than medulloblastoma have also undergone important changes in typing in the 2016 CNS WHO tumor classification. Atypical teratoid/rhabdoid tumor (AT/RT) is now defined by SMARCB1 (INI1) or very rare BRG1 mutations, so that the diagnosis of AT/RT in the future will require definitive and characteristic molecular testing. In addition, the molecular subtype “mucinous tumor of the pineal region with fibroproliferative properties, SMARCB1 mutant” has been named in the 2021 edition of the CNS classification.