Prospective study of circulating T-lymphocyte subpopulations and disease progression in colorectal cancer

Preoperative low absolute lymphocyte count to fibrinogen ratio correlated with poor survival in nonmetastatic colorectal cancer

Background

Preoperative absolute lymphocyte count (LC) and fibrinogen (FIB) are useful prognostic indicators in colorectal cancer (CRC). However, the prognostic value of the LC to FIB ratio (LFR) has never been addressed.

Methods

A total of 189 nonmetastatic CRC patients after resection were enrolled retrospectively. The significance of the LFR in predicting disease-free survival (DFS) and overall survival (OS) was estimated by receiver operating characteristic curve analysis, and the prognostic efficacy was compared with individual LC and FIB. Patients were assigned to LFR low or high subgroups. Differences in clinicopathological features among these subgroups were calculated, and the survival differences of these subgroups were determined by the Kaplan-Meier analysis. A Cox proportional hazards model was applied to test the risk factors for survival.

Results

Taking 0.54 as the optimal cutoff point, the LFR had sensitivities of 79.70% and 86.40% and specificities of 52.30% and 51.00% in predicting the DFS and OS, respectively. A total of 109/189 (57.67%) patients were assigned to the LFR low group, and these patients were more likely to be characterized by criteria such as T₃ + T₄ (P < 0.01), stage 3 (P < 0.01), tumor deposits (P = 0.01), high CEA (P < 0.01), or CA19-9 levels (P = 0.04). And they also displayed worse DFS (log rank = 18.57, P < 0.01) and OS (log rank = 20.40, P < 0.01) than the high LFR group. Finally, the LFR was independently associated with inferior DFS (HR = 0.32, 95% CI: 0.16–0.61, P < 0.01) and OS (HR = 0.23, 95% CI: 0.09–0.55, P < 0.01).

Conclusions

The LFR is a useful prognostic indicator in nonmetastatic CRC, and patients with a relatively low LFR had poor survival.

Application Value of Combined Detection of NLR, PNI, D-Dimer, CD3+ T Lymphocytes, and CEA in Colorectal Cancer Screening

Objective

To investigate the application value of combined detection of neutrophil-lymphocyte ratio (NLR), prognostic nutrition index (PNI), D-dimer (D-D), CD3⁺ T lymphocytes (CD3⁺ T), and carcinoembryonic antigen (CEA) in colorectal cancer screening.

Methods

The study cohort comprised 187 colorectal cancer patients and 100 mixed hemorrhoids patients as controls from January 2019 to August 2021 at the Fifth Affiliated Hospital of Sun Yat-sen University. Comparing the levels of NLR, PNI, D-D, CD3⁺ T, and CEA between the two groups of subjects, drawing receiver operating characteristic (ROC) curve evaluates the efficacy of single and combined detection for colorectal cancer screening.

Results

Compared with the control group, the levels of NLR, D-D, and CEA in the colorectal cancer group were significantly increased, while the levels of PNI and CD3⁺ T were significantly decreased (P < 0.05). ROC curve analysis showed that the combined detection of NLR, PNI, D-D, CD3⁺ T, and CEA for colorectal cancer screening had an AUC^ROC of 0.943, a sensitivity of 84.49%, a specificity of 91.00%, and a Youden index of 0.75, and its screening efficacy was significantly superior to that of a single detection (P < 0.001).

Conclusion

The combined detection of NLR, PNI, D-D, CD3⁺ T, and CEA has a high clinical application value for colorectal cancer and can provide a reference for early screening and auxiliary diagnosis of colorectal cancer.

Genome-wide multi-omics profiling of colorectal cancer identifies immune determinants strongly associated with relapse

The use and benefit of adjuvant chemotherapy to treat stage II colorectal cancer (CRC) patients is not well understood since the majority of these patients are cured by surgery alone. Identification of biological markers of relapse is a critical challenge to effectively target treatments to the ~20% of patients destined to relapse. We have integrated molecular profiling results of several "omics" data types to determine the most reliable prognostic biomarkers for relapse in CRC using data from 40 stage I and II CRC patients. We identified 31 multi-omics features that highly correlate with relapse. The data types were integrated using multi-step analytical approach with consecutive elimination of redundant molecular features. For each data type a systems biology analysis was performed to identify pathways biological processes and disease categories most affected in relapse. The biomarkers detected in tumors urine and blood of patients indicated a strong association with immune processes including aberrant regulation of T-cell and B-cell activation that could lead to overall differences in lymphocyte recruitment for tumor infiltration and markers indicating likelihood of future relapse. The immune response was the biologically most coherent signature that emerged from our analyses among several other biological processes and corroborates other studies showing a strong immune response in patients less likely to relapse.

Clinical implications and characteristics of factor forkhead box protein 3 in gastric cancer

Transcription factor forkhead box protein 3 (FOXP3) is a specific marker of naturally occurring regulatory T cells (Tregs). Recently, various reports have suggested that FOXP3 may represent a tumor escape mechanism in cancer cells apart from its roles in Tregs. In the present study, the clinical and biological characteristics of FOXP3 were evaluated in human gastric cancer. The expression and localization of FOXP3 in gastric cancer cell lines was analyzed to evaluate its cellular biological features. Sections of human gastric cancer specimens were stained using immunohistochemistry (IHC) to assess the relationship between FOXP3 expression and tumor differentiation, in order to identify its clinical characteristics in gastric cancer. Expression of FOXP3 mRNA and protein was found in four gastric cancer cell lines (AGS, SGC-7901, MKN-28 and MKN-45). IHC of the gastric cancer sections revealed that more than 56% of gastric cancers displayed nuclear or cytoplasmic FOXP3 staining. Furthermore, a linear relationship between the differentiation of the gastric cancer tissues and FOXP3 expression intensity was shown. IHC and confocal analysis showed that the expression of FOXP3 was mainly present in the nucleus of tumor cells in the tissues and cell lines. Thus, FOXP3 nuclear staining may be associated with the risk of poor tumor differentiation. Apart from the lymphocytes, no FOXP3 staining was noted in the normal gastric tissues and para-tumor tissues. The high frequency of FOXP3 expression in gastric cancer tissue is a significant finding in the investigation of tumor differentiation and immune escape. This mechanism provides a further understanding of gastric cancer and a novel therapeutic strategy is presented.

Circulating lymphocyte is an important determinant of the effectiveness of preoperative radiotherapy in advanced rectal cancer

Background

Although preoperative radiotherapy (RT) is widely used as the initial treatment for locally advanced rectal cancer (RC) in the neoadjuvant setting, factors determining clinical response have not been adequately defined. In order to find other factors possibly related with radiosensitivity, we evaluated the relationships between circulating blood cell counts and RT effects.

Methods

In 179 cases with advanced RC, we retrospectively examined hemoglobin (Hb) levels and counts of white blood cells (WBC), platelets and WBC subsets before and after RT and investigated their associations with the complete response (CR) rate together with other clinicopathological factors.

Results

The ratio of lymphocytes in WBC taken before RT was significantly greater in 15 CR cases as compared with those in non-CR cases. Patients with high lymphocyte percentages (25.7%) showed better outcome than the counterparts. Conversely, the ratio of neutrophiles was reduced in CR cases. The lymphocyte ratio showed an independent association with CR with multivariate analysis, and tended to be maintained at relatively high levels in CR cases.

Conclusions

In RC patients, peripheral blood lymphocytes have a significant impact on the CR rate in response to RT. Lymphocyte-mediated immune reactions are supposed to have positive roles on clinical response in radiotherapy for RC.

Host response to colorectal cancer

It has long been established that inflammation and immunity play critical roles in the pathogenesis, control and eventual metastasis of cancers. With the advent of more sophisticated animal models and immunohistochemical techniques a greater understanding of the immune system and its interactions has occurred. Individual immune cells are dynamic structures that have variable behaviour controlled by complex interactions in the tumour microenvironment. In the setting of colorectal cancer it was first observed that peritumoral inflammatory infiltrates were associated with improved prognosis. Immunohistochemistry has shown the individual cells types within these infiltrates. It now appears that an adaptive immune response, differentiated along the T-helper 1 pathway controls tumour invasion and metastasis. Furthermore, the immune system exerts selection pressure leading to the evolution of tumour cell variants that can induce tolerance and disable adaptive immunity. These tumour cells then use the mechanisms of innate immunity to facilitate further growth, angiogenesis, invasion and eventual metastasis. These issues are investigated with particular relevance to colorectal cancer. Using the immune response to defeat CRC has been under intense investigation but has so far been unsuccessful. Nevertheless, researchers remain optimistic that immunotherapy will play an important role in the treatment of this common disease.

Phenotype and function of dendritic cells and T-lymphocyte polarization in the human colonic mucosa and adenocarcinoma

AIM

To evaluate the status of activation of the intestinal dendritic cells (DCs) and T lymphocytes (T cells) from surgical specimens of human colon and adenocarcinoma, and the potential effect of administration of interleukin 2 (IL-2).

METHODS

Patients undergoing colectomy for cancer were randomized to receive subcutaneous IL-2 (12million UI/day) (treated group; n=10) for 3days before operation or no treatment (control group, n=10). DCs and T cells were isolated and purified from the lamina propria (LP) of segments of normal colon and adenocarcinoma of both groups. Cell phenotype was determined by expression of membrane receptors. Interaction between DC and T cells was assesses by a mixed leukocyte reaction using naïve T cells co-cultured with DCs. CD4+ T-cell polarization was studied by intracellular staining with monoclonal antibodies for interleukin-4 and interferon-gamma.

RESULTS

CD4+ T cells were significantly less in tumour than in LP (p<0.05) in both treated and control groups. IL-2 did not modify the number of any of the T-cell subsets analysed. In contrast, T cells isolated from LP and neoplasm of treated patients produced more interferon-gamma and less interleukin-4 (p<0.05 vs. controls). IL-2 administration significantly increased (p<0.05) the number of mature, myeloid and plasmocytoid DCs compared to controls. Allogeneic naïve T cells were polarized toward a Th1 type of response which appeared to be mediated by IL-2 activated DCs.

CONCLUSIONS

systemic IL-2 treatment may have immunomodulatory properties on intestinal DC maturation and drive a Th1 mediated anti-neoplastic response.

Pre-treatment white blood cell subtypes as prognostic indicators in ovarian cancer

OBJECTIVE

Inflammatory cells can both suppress and stimulate tumour growth and their influence on clinical outcome in cancer patients has been studied in various cancer types. Here we have investigated their influence on outcome in primary epithelial ovarian cancer.

STUDY DESIGN

Serum white blood cell numbers according to subtype were recorded prior to treatment in 136 patients with primary epithelial ovarian cancer. Their correlation with overall survival and disease-free survival was analysed using both univariate and multivariate analysis adjusting for the known prognostic factors (age, stage and debulking status).

RESULTS

Multivariate analysis demonstrated that a lower lymphocyte fraction of total white blood cells was significantly associated with mortality (p<0.01). On univariate analysis (p=0.0027, HR=1.15), and multivariate analysis of those patients who were optimally debulked (p=0.036, HR=1.17), a higher monocyte count was significantly associated with recurrence. On multivariate analysis amongst those who were suboptimally debulked, a higher eosinophil count was predictive of both recurrence (p=0.0037, HR=1.77) and mortality (p=0.033, HR=1.73).

CONCLUSION

High monocyte counts amongst those who were optimally debulked independently predict adverse outcome in primary epithelial ovarian cancer.

Depression, Immunity, and Survival in Patients With Hepatobiliary Carcinoma

Purpose

The aims of the present study were to assess the prevalence of depressive symptoms at diagnosis, test the association between depressive symptoms and survival, and preliminarily test a mediational model of depression, immunity, and survival in patients with hepatobiliary carcinoma (HBC).

Patients and Methods

One hundred one patients diagnosed with HBC were prospectively studied. Depressive symptoms were measured at diagnosis using the Center for Epidemiological Studies Depression Scale (CES-D). Sociodemographic and disease-specific data were gathered from the patients' charts. In a subsample of patients, stress; alcohol, tobacco, and drug use; sleep quality; physical activity; social support; natural killer (NK) cell number and cytotoxicity; and plasma levels of interleukin (IL) -4, IL-5, tumor necrosis factor alpha, and interferon gamma were measured. Survival was measured from date of diagnosis to death.

Results

At diagnosis, 37% of patients reported a CES-D score of ≥ 16 (clinical range). Using Cox regression analysis, sociodemographic and disease-specific variables and CES-D score significantly predicted survival (Breslow χ2= 32.4, P = .006). Only vascular invasion (P = .001) and CES-D score ≥ 16 (P = .03) were significant predictors. In a subsample of 23 patients, patients who reported a CES-D score of ≥ 16 were found to have significantly lower NK cell numbers than patients who reported a CES-D score of less than 16 (F1,21= 9.39, P = .003). A robust trend was found in which NK cell number was associated with survival. A mediational model linking depressive symptoms and survival, with NK cell number as a mediator, was preliminarily supported.

Conclusion

Secondary to the high prevalence of depressive symptoms and impact on survival, psychological and pharmacologic interventions should be designed and implemented in patients diagnosed with HBC.

Cloudy apple juice decreases DNA damage, hyperproliferation and aberrant crypt foci development in the distal colon of DMH-initiated rats

Clear (CleA) and cloudy (CloA) apple juices containing different amounts of analyzed procyanidins and pectin were investigated for preventive effects of colon cancer and underlying molecular mechanisms in F344 rats given intraperitoneal injections of 1,2-dimethylhydrazine (DMH; 20 mg/kg body wt) once a week for 4 weeks. Rats received either water (Cont), CleA or CloA (ad libitum) for 7 weeks starting 1 week before the first DMH injection. CloA inhibited DMH induced genotoxic damage in mucosa cells of the distal colon compared with Cont as investigated by single-cell microgel electrophoresis assay. The mean tail intensity in mucosa cells of DMH-treated controls (Cont/DMH: 6.1+/-0.9%) was significantly reduced by CloA (2.4+/-0.8%; P<0.01) but not by CleA intervention (4.1+/-1.2%; P>0.05). The crypt cell proliferation index induced by DMH (Cont/NaCl: 10.0+/-0.7%; Cont/DMH: 19.9+/-1.0%; P<0.001) was significantly decreased by CleA (15.7+/-0.7%; P<0.001) and CloA intervention (11.9+/-0.4%; P<0.001). CloA but not CleA significantly reduced the number of large aberrant crypt foci (ACF) consisting of more than four aberrant crypts (AC) (Cont/DMH: 37.4+/-5.4; CleA/DMH: 32.8+/-4.4, P>0.05; CloA/DMH: 18.8+/-2.5 ACF; P<0.05) and the overall mean ACF size in the distal colon (Cont/DMH: 2.31+/-0.09; CleA/DMH: 2.27+/-0.05; CloA/DMH: 2.04+/-0.03 AC/ACF; P<0.05). After treatment with DMH and/or apple juices there were no changes in transcript levels of colonic cyclooxygenase isoforms (COX-1, COX-2) or glutathione-associated enzymes (GST-M2, gamma-GCS, GST-P), the splenocyte natural killer cell activity and plasma antioxidant status. However, CloA but not CleA prevented the DMH-induced reduction of splenocyte CD4/CD8 (T-helper cells to cytotoxic lymphocytes) ratio. Since both formulations contained comparable concentrations and types of monomeric polyphenols, complex polyphenols or non-polyphenolic compounds, such as pectin might be responsible for the stronger cancer-preventive effect by CloA.

Tumour T-lymphocyte subset infiltration and tumour recurrence following curative resection for colorectal cancer

AIM

The relationship of tumour T-lymphocytic subset infiltration and recurrence in patients undergoing potentially curative resection for colorectal cancer has not been clearly defined.

METHODS

Tumour sections from patients who had undergone potentially curative resection for colorectal cancer were stained and counted for CD4+ and CD8+ T-lymphocytes.

RESULTS

Twenty-three patients developed recurrence during the follow-up period. Patients were grouped according to whether or not they developed recurrence. The groups were similar in age, sex, site of tumour, Dukes stage and the numbers of patients receiving adjuvant therapy. The total percentage volume of labelled CD4+ T-lymphocytes in the tumour was significantly lower in the patients who recurred (p<0.05).

CONCLUSIONS

The results of the present pilot study suggest that a reduction in tumour T-lymphocyte infiltration, in particular CD4+ T-lymphocyte infiltration, is associated with recurrence in patients following potentially curative resection for colorectal cancer.

Lymphocyte subsets and natural killer cell cytotoxicity after laparoscopically assisted resection of rectosigmoid carcinoma

BACKGROUND

Laparoscopically assisted resection of colorectal carcinoma is technically feasible and minimally invasive. Postoperative immunosuppression also may be reduced. This study compared the lymphocyte subsets and natural killer (NK) cell cytotoxicity in patients after laparoscopically assisted resection with those after open resection of rectosigmoid carcinoma.

METHODS

In this study, 40 patients with rectosigmoid carcinoma, but no evidence of metastasis, were randomized to receive either laparoscopically assisted or conventional open resection of the tumor. Blood was collected before the operation, then 24 h, 72 h, and 8 days after the operation for studies of lymphocyte subsets and NK cell cytotoxicity.

RESULTS

The lymphocyte subsets and NK cell cytotoxicity of both groups showed typical suppression after surgery. The suppression of T cell activation and NK-like T cells was significantly less after laparoscopically assisted resection than in after open resection, whereas the difference in other lymphocyte subsets and NK cell cytotoxicity was not significant.

CONCLUSION

This study showed that some cellular components of the immune system are less suppressed after laparoscopically assisted than after conventional open resection of rectosigmoid carcinoma. This may have implications for tumor recurrence and long-term patient survival.

Physical exercise and immune system function in cancer survivors: a comprehensive review and future directions

BACKGROUND

There are a limited number of interventions for cancer survivors following completion of primary therapy that might reduce the risk of cancer recurrence and/or secondary malignancies and increase survival times. It has been proposed that physical exercise may be beneficial by enhancing the anticancer immune system response. The purpose of the current article is to: 1) briefly describe the immune system response to tumors, 2) discuss the impact of anticancer therapy on immune system function in cancer survivors, 3) provide a systematic and comprehensive review of the extant literature examining physical exercise and immune system function in cancer survivors, and 4) offer a critical analysis of this literature and outline directions for future research.

METHODS

A comprehensive literature search up to March 2001 identified empirical articles that examined the effects of physical exercise training on immune system function in cancer survivors from CD-ROM database searches and manual searches.

RESULTS

To the authors' knowledge, six empirical studies published between 1994 and 2000 have examined physical exercise and immune system function in cancer survivors. Overall, four out of six studies reported statistically significant improvements in a number of cancer-related immune system components as a result of exercise. However, there are several limitations that must be considered when interpreting the findings of these studies. These limitations involve the samples, designs, physical exercise interventions, physical fitness assessments, and immunologic assessments.

CONCLUSIONS

Additional research is needed to determine if physical exercise in cancer survivors may reduce the risk of cancer recurrence and secondary malignancies and increase survival times.

T cell responses in colorectal cancer patients: evidence for class II HLA-restricted recognition of shared tumor-associated antigens

Few cases of anti-colon cancer specific T lymphocytes have been described so far. Moreover, the majority of these effectors were generated in vitro by stimulating PBMC from patients or healthy donors with peptides that were derived from proteins expressed and/or secreted by colon cancer tissue such as CEA, Mucin or Her-2/neu. The aim of our study was to evaluate the immunogenicity of colorectal carcinomas in an autologous setting. We exploited the antigen processing and presentation capacity of dendritic cells (DC) to establish an in vitro autologous system that can bypass the need of obtaining cultured tumor cells. DC were generated from the adherent monocyte fraction of PBMC taken from stage II/III colorectal cancer patients. A single cell suspension was prepared by mechanical and enzymatic disruption of the surgical specimens immediately after resection. DC were loaded with autologous tumor lysate, obtained by repeated freezing and thawing, before being used as stimulators for autologous PBL. HLA-class II restricted T cells that recognize the autologous tumor could be generated in a proportion of patients. The fine specificity of the anti-tumor T cells indicates that differentiation as well as tumor restricted antigens are expressed in colon cancer and that these antigens can evoke a class II HLA-restricted response in an autologous setting. Altogether these findings may open a new perspective for a DC based vaccination of colon cancer patients.

Preoperative elevation of serum C-reactive protein is related to impaired immunity in patients with colorectal cancer

The significance of a preoperative elevation of serum C-reactive protein (CRP) as an indicator of the malignant potential and prognosis in colorectal cancer is reported. The reduction of circulating lymphocytes reflects the immunosuppressive conditions of patients with neoplasms. The aim of the current study was to elucidate the significance of a preoperative elevation of serum CRP as an indicator of the impaired immunity of the patients with colorectal cancer. The subjects were 155 consecutive patients with colorectal cancer who were treated with surgical resection. The preoperative serum CRP level and the proportion of circulating lymphocytes in peripheral blood were measured and the relationship between these values was investigated. The mean value of lymphocytes percentages in patients with the preoperative elevation of serum CRP was 25.2 +/- 8.7%, which was significantly lower than that (33.4 +/- 9.3%) in patients without the preoperative elevation of serum CRP (p < 0.01). In summary, preoperative elevation of serum CRP was significantly related to the reduction of lymphocyte percentages in peripheral blood, and it can be an indicator of impaired immunity in the patients with colorectal cancer.

Rectal cancer recurrence: factors and mechanisms

OBJECTIVE

There have been significant developments in treatment for rectal carcinoma, both in surgical and adjuvant therapy. They may however have associated morbidity and hence individualized therapy for rectal cancer is desirable, to optimize treatment but avoid over-treatment for cases where the risk of recurrence is low.

MATERIALS AND METHODS

A literature review was undertaken of the reported incidence of recurrence of rectal carcinoma following curative surgery, factors which predispose to recurrence and proposed mechanisms for recurrence, and the evidence for each critically evaluated.

RESULTS

The incidence of local recurrence of rectal carcinoma following curative resection ranges from 2.6% to 32%, with an average of 15%. Tumour stage is the strongest predictor of tumour recurrence. Upstaging using molecular biology may predict increased risk of recurrence but is not yet proven. Histological factors including differentiation and vascular invasion increase recurrence but are imprecise. Tumour microvascular density and vascular endothelial growth factor (VEGF) levels may be predictive but need refinement. Adequate resection margins are important but recurrence may occur despite this. Tumour cell spillage and distant dissemination may be a mechanism for tumour recurrence following curative resection, but further research is required before this could be applied clinically.

CONCLUSION

Recurrence of rectal cancer remains a significant problem following 'curative' surgery. Multiple factors may influence recurrence risk, though currently however only tumour stage and histological resection margins have demonstrated sufficient importance for management decisions to be made upon them.

Immunology and immunotherapy of human cancer: present concepts and clinical developments

Immunotherapy of cancer is entering into a new phase of active investigation both at the pre-clinical and clinical level. This is due to the exciting developments in basic immunology and tumour biology that have allowed a tremendous increase in our understanding of mechanisms of interactions between the immune system and tumour cells. This review briefly summarizes the state of the art in basic tumour immunology before discussing the clinical applications of the new concepts in the clinical setting. Clinical approaches are diverse but can now be based on strong scientific rationales. The analysis of the available clinical results suggests that, despite some disappointments, there is room for optimism that both active immunotherapy (vaccination) and adoptive immunotherapy may soon become part of the therapeutic arsenal to combat cancer in a more efficient way.

Reduction in cytokine production in colorectal cancer patients: association with stage and reversal by resection

The aim of this study was to assess monocyte/macrophage function, as defined by lipopolysaccharide (LPS)-induced production of tumour necrosis factor (TNF)-alpha, interleukin (IL)-10 and interferon (IFN)-gamma by stimulated whole blood cultures in patients with colorectal carcinoma before and after surgical resection. Forty colorectal cancer patients prior to surgery and 31 healthy controls were studied. Heparinized venous blood was taken from colorectal cancer patients prior to surgery and from healthy controls. Serial samples were obtained at least 3-6 weeks post-operatively. Blood was stimulated with LPS for 24 h and supernatants were assayed for TNF-alpha, IFN-gamma and IL-10 by enzyme-linked immunosorbent assay. LPS-induced production of TNF-alpha and of IFN-gamma was reduced in patients with colorectal carcinoma compared to controls (TNF-alpha, 11,269 pg/ml(-1) ¿12,598¿; IFN-gamma, 0.00 pg/ml(-1) ¿226¿; median ¿IQR¿) (TNF-alpha, 20,576 pg/m(-1) ¿11,637¿, P < 0.0001; IFN-gamma, 1,048 ¿2,428¿, P = 0.0051, Mann-Whitney U-test). Production in patients after surgery had increased (TNF-alpha: 17,620 pg/ml(-1) ¿7,986¿; IFN-gamma. 410 pg/ml(-1) ¿2,696¿; mean ¿s.d.¿) and were no longer significantly reduced when compared to controls (TNF-alpha, P = 0.28; IFN-gamma, P = 0.76). Production of TNF-alpha and IFN-gamma prior to surgery were reduced to a greater extent in patients with Dukes' stage C tumours compared to those with Dukes' stage A and B stage. There was no difference in IL-10 production between any group. Monocytes/macrophages from patients with colorectal carcinoma are refractory to LPS stimulation as reflected by reduction in TNF-alpha and IFN-gamma production and this is more pronounced in patients with advanced stage tumours. This suppression is not mediated by IL-10 and disappears following surgical resection of the tumour. This provides evidence for tumour induced suppression of immune function in patients with colorectal cancer and identifies a potential therapeutic avenue.