CA appearance in weeks	Number of Cell lines	(%) of 225 Lines Screened
negative	148	65.8
1-2	8	3.6
3-4	36	16.0
5-6	28	12.4
7-8	5	2.2
Total positive:	77	34.2

Stroma were seeded with day 2 post 5 FU (7037434) bone marrow and observed weekly for the appearance of cobblestone areas (CAs) (2819245).