A comparison of two culture techniques: An in vitro & an in vivo tumour colony-forming assay

Twenty-one identical tumour specimens were cultured both in the Plasma-Clot Diffusion Chamber (PCDC) Technique and the Human Tumour Colony-forming Assay (HTCA). The culture results achieved in the PCDC-technique were clearly superior to the HTCA: in the PCDC the mean and median plating efficiency (PE) was 0.156 and 0.147, in the HTCA 0.103 and 0.028%; adequate growth rate in the PCDC-technique was 67% and in the HTCA 38%. Fewer cells were required for plating in the PCDC-technique: 6.4 X 10(4) vs. 2.6 X 10(5) in the HTCA. The mean and median coefficient of variation of the colony numbers in the PCDC-technique appeared much higher: 27.3 and 37.3 vs. 11.2 and 11.1% in the HTCA. The relation between the PEs obtained for the same specimen in the two techniques was compared. No positive correlation was found, which can possibly be ascribed to technical shortcomings in both techniques.