Table 1. Concentration of CA IX in biological materials.

HT29 cell extracta	4 mg g−1 total protein
Fresh RCC extract	0.5–2 mg g−1 total protein
Normal kidney extract	Not detectable
HT29 TC mediuma	20–50 ng ml−1
RCC TC media	20–50 ng ml−1
Sera of RCC patients	20 pg–3.6 ng ml−1
Control sera	5–25 pg ml−1
Urine of RCC patients	20 pg–3 ng ml−1
Control urine	0–2 pg ml−1

^aA 5-cm Petri dish corresponds to 5 ml of medium or to 0.5 mg total protein extracted from the cell monolayer.