Mammosphere culture of metastatic breast cancer cells enriches for tumorigenic breast cancer cells

Breast Cancer Research

Table 1 Surface phenotype and mammosphere culture of cells from pleural effusions

Sample	Average size of mammospheres (μm)	Population of CD44⁺/CD24^low/- cells (percentage)
PE33	No mammospheres^a	14.2
PE61	No mammospheres
PE70	No mammospheres	37
PE75	No mammospheres	62
PE77	No mammospheres	18.8
PE78	No mammospheres	10.4
PE89	No mammospheres
PE19	20	67.9
PE20	20	0.3
PE22	20
PE23	20	65
PE62^b	20	13.2
PE63	20
PE88^b	20	37
PE6^b	30	1.5
PE79	40	4.8
PE11	50	26
PE43^b	50	9.9
06PE5^c	50
06PE7^c	50
PE73	60	29.4
06PE4^c	60	4.9
06PE8^b,c	70	70.6
PE14^b	100	Uncultured cells uniformly CD44^- and CD24^-
PE21	100	3.3
06PE6^b,c	100	15.3
PE66^b	130	6.85

Cells from pleural effusion (PE) samples taken from breast cancer patients were tested for their ability to form mammospheres. Uncultured cells were analysed for surface expression of CD24 and CD44 (Figure 3). ^a7/27 (26%) did not make mammospheres or could not be passaged beyond passage 2. ^bTested for tumorigenicity in severe combined immunodeficiency disease mice (Table 2). ^cFive samples obtained in 2006 were placed into culture without freezing. The other 22 samples obtained from 1977 to 1984 had been stored in liquid nitrogen.

ISSN: 1465-542X