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What is known about the biology of each subtype of Renal Cell Carcinoma?

Papillary renal cell carcinoma

Papillary renal cell carcinoma (PRCC) in children is identical to the papillary renal cell carcinomas seen in adults. It has the same genetic abnormalities, such as a gain of extra chromosomes 7 and 17 (trisomy 7 and 17). Papillary renal cell carcinomas are divided into two groups, type 1 and type 2. Type 1 has changes in the MET gene and type 2 has been associated with the FH gene.

Renal medullary carcinoma

Renal medullary carcinoma is almost always found in children who have the sickle cell trait, and is sometimes found in children with sickle cell anemia (a blood disorder). Adults, up to middle age, and children as young as 3 years old, can get this tumor. However, the average age is 13 years old. The relationship between renal medullary carcinoma and sickle cell trait is currently unclear. Almost all known cases have an African American heritage, but patients with Caucasian European and Brazilian background have also been reported. Renal medullary carcinoma is a very difficult tumor to treat. It is treated with radiation and chemotherapy. However, the tumor is not usually found until after the tumor has spread, so chemotherapy and radiation does not work as well as if it was found in its early stages. One reason for why renal medullary carcinoma spreads so easily to nearby structures is that there is not a good barrier for containing the tumor, so the tumor can spread more easily to nearby structures. Another reason is that there is often more than one tumor present. The average length of survival ranges from 2-15 months, but is usually closer to 4 months.

Renal cell carcinoma with TFE3 or TFEB translocations

Renal cell carcinoma, with TFE3 or TFEB translocations, is a heterogeneous group of tumors (mixture of several types of tumors) that are more common in children than adults. This kind of renal cell carcinoma frequently spreads outside of the kidney (for example into blood vessels or lymph nodes) and spreads irregularly into the kidney that is next to the tumor.

Almost all tumors in this subgroup have a mutation where the X chromosome has joined together with another chromosome at the Xp11.2 locus (specific chromosome position). The gene involved on the X-chromosome is called TFE3. A newly developed test for TFE3 allows pathologists to definitively recognize this tumor under the microscope.

A closely related subtype has a mutation where the chromosome 6 gene (TFEB) combines to the chromosome 11 gene (Alpha). The TFEB gene belongs to the same gene family as TFE3 so these tumors look very similar under the microscope. This subtype is confirmed by the pathologist when the tumor stains for special markers called HMB45 and Melan A.

Renal cell carcinoma, conventional (clear cell) subtype

This subtype of renal cell carcinoma is the most common renal cell carcinoma subtype. However, diagnosis of conventional (clear cell) type renal cell carcinoma is highly unlikely in a patient under the age of 20 unless the child has a genetic syndrome such as von Hippel-Lindau (VHL) or tuberous sclerosis (TS). This subtype of RCC often has a change in the VHL gene located at chromosome 3p25. A careful examination by a specialized pathologist using special markers is highly recommended.

More information for Health Professionals

More information about the pathology or genetics of these subtypes.