Immunological environment in colorectal cancer: a computer-aided morphometric study of whole slide digital images derived from tissue microarray

Summary Cancer research has moved from investigating tumour cells to including analysis of the tumour microenvironment as well. The aim of this study was to assess the cellular infiltrateof colorectal cancer (CRC) using computer-aided analysis of whole slide digital image derivedfrom tissue microarray(TMA). TMA slides from 31 CRC patients were immunostained for forkhead box protein 3 ( FOXP3) and immunomodulatory enzyme indoleamine 2,3-dioxygenase(IDO) at four sites: centre (C) and invasive front (F) of the tumour, proximal non-metastatic draining lymph node (N–), tumour-draining lymph node with metastasis (N+) and healthy mucosa at 10 cm from the cancer (M). We analysed the proportion of IDO+ tissue areas in the lamina propriaor in the non-epithelial area of the lymph node and in epithelial cells in each site. The normal mucosa of patients operated on for benign disease was also analysed. The proportion (%) of FOXP3+ tissue area in C, F, N–, N+ and M were 2.3 ± 1.8, 2.6 ± 2.9, 6.0 ± 2.9, 14.2 ± 5.8 and 1.2 ± 0.8 ( p p p r = 0.44, p