Gene expression profiling of renal medullary carcinoma: potential clinical relevance.
BACKGROUND
Renal medullary carcinoma is a rare kidney tumor with highly aggressive behavior. This tumor occurs exclusively in young patients with sickle cell trait or disease. To the authors' knowledge, very little is known to date regarding the underlying molecular genetics of this tumor, and no effective therapy has been established.


METHODS
The authors analyzed the gene expression profiles of 2 renal medullary carcinomas from patients with sickle cell trait using microarrays containing 21,632 cyclic DNA (cDNA) clones and compared them with the gene expression profiles of 64 renal tumors.


RESULTS
Based on global gene clustering with 3583 selected cDNAs, the authors found a distinct molecular signature of renal medullary carcinoma, which clustered closely with urothelial (transitional cell) carcinoma of the renal pelvis, rather than renal cell carcinoma (RCC). This finding of a significant difference in the gene expression patterns of renal medullary carcinoma compared with RCC suggests that this tumor should not be treated as a conventional RCC but, rather, as a special malignancy. This study also identified genes/proteins that may serve as biomarkers for renal medullary carcinoma or as potential targets of novel therapies. In addition, comparative genomic microarray analysis allowed the authors to predict the lack of chromosomal imbalances in this tumor.


CONCLUSIONS
To the authors' knowledge, the current study is the first molecular profiling of renal medullary carcinoma, a rare but highly aggressive kidney carcinoma. The genes that are expressed specifically in this tumor may lead to not only a better understanding of its molecular pathways and discoveries of novel diagnostic markers but also, more important, to effective therapeutic interventions.
Yang
Ximing J
XJ
Department of Pathology, The University of Chicago, Chicago, Illinois, USA.
Sugimura
Jun
J
Tretiakova
Maria S
MS
Furge
Kyle
K
Zagaja
Gregory
G
Sokoloff
Mitchell
M
Pins
Michael
M
Bergan
Raymond
R
Grignon
David J
DJ
Stadler
Walter M
WM
Vogelzang
Nicholas J
NJ
Teh
Bin Tean
BT
D000328:Adult; D001707:Biopsy, Needle; D018276:Carcinoma, Medullary / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D018450:Disease Progression; D017809:Fatal Outcome; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D015723:Gene Library; D006801:Humans; D007680:Kidney Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D008297:Male; D009367:Neoplasm Staging; D009392:Nephrectomy