Tumour infiltrating lymphocytes and apoptosis are independent features in colorectal cancer stratified according to microsatellite instability status

• Published in: Gut 2001-03, Vol.48 (3), p.360-366
• Main Authors: Michael-Robinson, J M, Biemer-Hüttmann, A-E, Purdie, D M, Walsh, M D, Simms, L A, Biden, K G, Young, J P, Leggett, B A, Jass, J R, Radford-Smith, G L
• Format: Article
• Language: English
• Subjects: Adenocarcinoma - genetics; Adenocarcinoma - pathology; Aged; Analysis of Variance; Antigens, CD20 - immunology; Apoptosis; Apoptosis - physiology; Biological and medical sciences; CD3 Complex - immunology; CD8 Antigens - immunology; Cell Count; Cloning; Colorectal cancer; Colorectal Neoplasms - genetics; Colorectal Neoplasms - pathology; Deoxyribonucleic acid; DNA; DNA microsatellite instability; Female; Gastroenterology. Liver. Pancreas. Abdomen; Genes, p53 - genetics; Growth factors; Humans; Immunohistochemistry; Laboratories; Lymphocytes; Lymphocytes, Tumor-Infiltrating - physiology; Male; Medical prognosis; Medical sciences; Microsatellite Repeats - genetics; Mutation; Pathology; Physiological aspects; Polymorphism, Single-Stranded Conformational; Prognosis; Statistics, Nonparametric; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Tropical medicine; Tumor-infiltrating lymphocytes; Tumors; tumour infiltrating lymphocytes
• ISSN: 0017-5749; 1468-3288; 1458-3288
• DOI: 10.1136/gut.48.3.360

BACKGROUND The presence of high level DNA microsatellite instability (MSI-H) in colorectal cancer is associated with an improved prognosis, as is the presence of tumour infiltrating lymphocytes (TILs). It is not clear if TILs contribute directly to the survival advantage associated with MSI-H cancers through activation of an antitumour immune response. AIMS To correlate TIL and apoptosis rates in colorectal cancer stratified by MSI status. METHODS The distribution of TILs was characterised and quantified in a selected series of 102 sporadic colorectal cancers classified according to levels of MSI as 32 MSI-H, 30 MSI-low (MSI-L), and 40 microsatellite stable (MSS). Archival blocks were immunostained using the T cell markers CD3 and CD8, and the B cell marker CD20. Apoptosis of malignant epithelial cells was quantified by immunohistochemistry with the M30 CytoDEATH antibody. RESULTS Positive staining with anti-CD3 and negative staining with anti-CD20 identified virtually all TILs as T cells. The majority of CD3+ TILs (>75%) also stained with anti-CD8. TILs were most abundant in MSI-H colorectal cancers in which 23/32 (72%) scored as TIL positive. Only 5/40 (12.5%) MSS tumours and 9/30 (30%) MSI-L cancers were TIL positive (p