Role of infiltrated leucocytes in tumour growth and spread

Abstract

Leucocytes are a major component of the tumour microenvironment. Recent studies have indicated that the infiltration and activity of these host cells are regulated by the tumour to promote its survival and progression. Through the production of an array of growth factors, proteases and angiogenic mediators, leucocytes in the tumour microenvironment promote tumour growth, angiogenesis and metastasis.

Evaluation of the prognostic value of systemic inflammation and socioeconomic deprivation in patients with resectable colorectal liver metastases

“…26 This phagocyte class exerts a number of biological actions in common with neutrophils that may explain this prognostic value. 8 In this study no association was found between the peripheral lymphocyte count and outcome following CLM resection, even when further analyses were conducted to evaluate multiple cut-off points (data not shown).…”

“…23,39 Whilst it is possible that increasing neutrophil count is simply an epiphenomenon of the inflammatory response in the vicinity of the tumour, the emerging theory of 'immune enhancement' suggests that cells of the myeloid lineage, particularly neutrophils, are recruited from the circulation and play a direct role in promoting aggressive tumour phenotypes. 8,9 Neutrophils are the major producers of a number of ligands that may induce tumour cell proliferation and invasion, including transforming growth factor-. 43 Furthermore, granulocytes, particularly neutrophils, contain over two-thirds of circulating vascular endothelial growth factor, liberation of which may promote tumour vascularisation.…”

“…5,6 In addition to intrinsic tumour factors, patient prognosis is also influenced by the host inflammatory response to malignancy, with data supporting a direct role for inflammatory cells and mediators in the promotion of both primary tumour growth and disease dissemination. 7,8 At the local level, the immune response involves infiltration of the tumour environment by both lymphocytes and cells of myeloid lineages. 8,9 The degree of this local inflammatory cell infiltration has been shown to have prognostic significance in numerous malignancies, including primary colorectal cancer (CRC).…”

“…7,8 At the local level, the immune response involves infiltration of the tumour environment by both lymphocytes and cells of myeloid lineages. 8,9 The degree of this local inflammatory cell infiltration has been shown to have prognostic significance in numerous malignancies, including primary colorectal cancer (CRC). 8,10,11 A systemic inflammatory response (SIR), more easily assessable preoperatively, accompanies the local immune response, driven by the production of pro-inflammatory cytokines, including interleukin-1 , interleukin-6 and tumour necrosis factor-by both tumour cells and recruited immune cells.…”

“…8,9 The degree of this local inflammatory cell infiltration has been shown to have prognostic significance in numerous malignancies, including primary colorectal cancer (CRC). 8,10,11 A systemic inflammatory response (SIR), more easily assessable preoperatively, accompanies the local immune response, driven by the production of pro-inflammatory cytokines, including interleukin-1 , interleukin-6 and tumour necrosis factor-by both tumour cells and recruited immune cells. 12 These cytokines stimulate the release of acute phase proteins, most notably C-reactive protein (CRP).…”