tokens: The reported frequency of detection of VHL germline mutations has varied from 39 to 80 % ( J . M . Whaley et al . , Am . J . Hum . Genet . , 55 1092 - 1102 , 1994 ; Clinical Research Group for Japan , Hum . Mol . Genet . , 4 2233 - 2237 , 1995 ; F . Chen et al . , Hum . Mutat . , 5 66 - 75 , 1995 ; E . R . Maher et al . , J . Med . Genet . , 33 328 - 332 , 1996 ; B . Zbar , Cancer Surv . , 25 219 - 232 , 1995 ) .