Methods

Collection and Histopathological Analysis of Tumour Samples

Only tumour samples collected prior to any treatment will be selected. Tumour samples are obtained from the clinics where the cases undergo biopsy or surgical resection. These specimens are fixed in fresh-buffered formalin and paraffin-embedded (FFPE) according to standard protocols. Paraffin blocks are kept at the local pathology service facilities in controlled storage conditions. Only the slides necessary for analyses will be sent to the Porter Lab at Fred Hutchinson Cancer Research Center (FHCRC) in Seattle, USA.

Identical protocols are used for processing and testing block selection. Haematoxylin and eosin (H&E) sections are made at the centres, and data concerning the histological diagnosis and pathological features of the tumour are collected on a standard form by the designated study pathologist at each centre. Under the direction of Dr Porter and prior to the start of the pathology review, study pathologists agreed on the diagnostic and pathology criteria and a training study set of breast cancer slides was used to identify and resolve differences in diagnostic criteria among the pathologists.