<prompt> A 40 year old man presented with painless hematuria Bimanual examination revealed a ballotable mass over the right flank. Subsequently right nephrectomy was done and mass was seen to be composed of cells with clear cytoplasm. Areas of hemorrhage and necrosis were frequent. Cytogenic analysis of this mass is likely to reveal an abnormality of:Chromosome 1Chromosome 11Chromosome 3Chromosome 17  <response>: Answer is C Chromosome-3 Presence ofpainless haematuria with balottable muss in right flank in this foy years old male suggests diagnosis of renal cell carcinoma. The most common histological variant clear cell carcinome is associated with a defect in chromosome 3. 