(b).

Chromosome	Type of genetic alteration	Candidate gene	Incidence	Function of protein	Prognosis
Chromosome 7	Polysomy	NA	Polysomy 7 in 50–100% pRCC [133, 181, 182]	NA	Polysomy 7 is not correlated with survival, clinical features, or proliferation rate of pRCC [132, 133, 136, 137]
7q31	Missense mutation, gene duplication	MET	MET mutation present in 5–21.6% of sporadic pRCC [8, 108, 139, 141]; copy number gains in 46% of type II pRCC and in 81% of type I pRCC [108]; strong c-met protein expression in 80–90% of sporadic pRCC [143, 144]	The c-met protein is involved in cell proliferation, motility, differentiation, invasion, and angiogenesis [142, 143]	One study showed association of increasing tumour stage with c-met expression and a trend of better overall survival in patients with no c-met expression in tumours [143]
Chromosome 17	Polysomy	NA	Gains in 14.3–95.5% of pRCC [132, 134, 137, 158, 183]	NA	Trisomy 17 associated with better prognosis (lower stage, less nodal involvement and metastases, longer survival) [137, 138]; Balint et al. showed no link with tumour size and grade [132]
Chromosome Y	Loss	NA	Affects 71–87% of tumours in men [137, 138, 158, 184]	NA	Loss of chromosome Y not linked to pathological variables and survival [137]
Chromosome X	Loss	NA	Loss involving Xp in 28% and Xq in 36% of pRCC tumours [158]	NA	Losses of chromosome Xp associated with short patient survival [158]
3p	loss	NA	Allelic changes in 14–37.5% of tumours [137, 185]	NA	Loss of 3p associated with higher stage and grade, lymph node involvement, distant metastasis, larger tumour size, and worse survival [137]
Gains of 1q, chromosomes 12, 16, and 20; losses of 1p, 4q, 5q, 6q, 8p, 9p, 11, 13q, 14q, and 18 [135, 137, 138, 158, 186]					Loss of 9p associated with higher stage, larger tumour size, metastasis, lymph node involvement, recurrence, and decreased survival [137, 138]; losses of 8p and chromosome 18 correlated with higher stage, metastasis, and worse recurrence free survival [138]

NA indicates not available.