Table 2.

Distribution of quality control measures for tissue cores stained for ER, PR and HER2 in the virtual TMAs

Quality control category	ER		PR		HER2
	N	%	N	%	N	%
Satisfactory Core (invasive tumour)	649	69	679	71	672	67
DCIS only	61	6	52	5	82	8
No Tumour, few tumour cells	123	13	98	10	126	13
No core	38	4	32	3	48	5
Unsatisfactory core for other reasons	71	8	91	10	70	7
Total	942		952		998