Active specific immunotherapy in colon cancer

Lymph node yield after colectomy for cancer: is absence of mismatch repair a factor?

BACKGROUND

Nodal staging is crucial in determining the use of adjuvant chemotherapy for colon cancer. The number of metastatic lymph nodes has been positively correlated with the number of lymph nodes examined. Current guidelines recommend that at minimum 12 to 14 lymph nodes be assessed. In some studies, mismatch repair deficiency has been associated with lymph node yield.

OBJECTIVE

The purpose of this work was to determine whether mismatch repair-deficient colorectal tumors are associated with increased lymph node yield.

DESIGN

We queried an institutional database to analyze colectomy specimens with immunohistochemistry for mismatch repair genes in patients treated for colorectal cancer between 1999 and 2012. Before 2006, immunohistochemistry was performed at the request of an oncologist or surgeon. After 2006, it was routinely performed for patients <50 years of age. We measured the association of clinical and pathologic features with lymph node quantity. Fourteen predictors and confounders were jointly analyzed in a multivariable linear regression model.

SETTINGS

The study was conducted at a single tertiary care institution.

PATIENTS

Tissue specimens from 256 patients were reviewed.

MAIN OUTCOME MEASURES

The correlation of tumor, patient, and operative variables to the yield of mesenteric lymph nodes was measured.

RESULTS

Of 256 colectomy specimens reviewed, 94 had mismatch repair deficiency. On univariate analysis, mismatch repair deficiency was associated with lower lymph node yield, older patient age, right-sided tumors, and poor differentiation. The linear regression model identified 5 variables with independent relationships to lymph node yield, including patient age, specimen length, lymph node ratio, perineural invasion, and tumor size. A positive correlation was observed with tumor size, specimen length, and perineural invasion. Tumor location had a more complex, nonlinear, quadratic relationship with lymph node yield; proximal tumors were associated with a higher yield than more distal lesions. Mismatch repair deficiency was not independently associated with lymph node yield.

LIMITATIONS

Mismatch repair immunohistochemistry based on patient age, family history, and pathologic features may reduce the generalizability of these results. Our sample size was too small to identify variables with small measures of effect. The retrospective nature of the study did not permit a true assessment of the extent of mesenteric resection.

CONCLUSIONS

Patient age, length of bowel resected, lymph node ratio, perineural invasion, tumor size, and tumor location were significant predictors of lymph node yield. However, when controlling for surgical and pathologic factors, mismatch repair protein expression did not predict lymph node yield.

Tumor infiltrating lymphocytes: an intriguing player in the survival of colorectal cancer patients

Background

There is growing evidence that both local and systemic inflammatory responses play an important role in the progression of a variety of solid tumors. Colorectal cancer results from the cumulative effect of sequential genetic alterations, leading to the expression of tumor associated antigens possibly inducing a cellular anti-tumor immune response. It is well recognized that cytotoxic lymphocytes constitute one of the most important effector mechanisms of anti-tumor-immunity. However, their potential prognostic influence in colorectal cancer remains controversial. Aim of the study was to examine infiltration of CD3⁺ and CD8⁺ lymphocytes in colorectal cancer and their prognostic potential.

Two-hundred-fifteen colorectal cancer cases, previously analyzed for microsatellite instability (MSI), were selected for immunohistochemical detection of CD3⁺, CD8⁺ infiltration and the expression of granzyme B. Prognostic relevance was assessed by survival analysis.

Results

Strong correlations were found between the infiltration of lymphocytes and several clinicopathological variables. Survival analysis revealed that intra-epithelial infiltration of CD3⁺ and CD8⁺ T lymphocytes and stromal infiltration of CD3⁺ lymphocytes had a major impact on the patients' overall survival in the univariate analysis, however independent of their association with MSI-status. In addition, it was also demonstrated that there was an important disease specific survival advantage for patients with microsatellite stable (MSS) tumors containing intraepithelial CD8⁺ tumor infiltrating lymphocytes. When samples were analyzed for colon cancer and rectal cancer separately, the results of the overall population were confirmed in colon cancer only. When entered into a multiple Cox regression analysis adjusting for other possible important confounding factors, the strong impact of lymphocyte infiltration on overall survival was not maintained. Only early stage and young age (borderline significant for overall population only) were associated with a better overall survival (early disease with disease-free survival also).

Conclusions

In conclusion our results suggest a role for infiltrating CD3⁺ and CD8⁺ T lymphocytes in colorectal cancer whereby tumor infiltration could reflect a general principle of antitumor immunity, irrespective of the MSI-status.

Combination of active specific immunotherapy or adoptive antibody or lymphocyte immunotherapy with chemotherapy in the treatment of cancer

Successful treatment of cancer patients with a combination of monoclonal antibodies (mAb) and chemotherapeutic drugs has spawned various other forms of additional combination therapies, including vaccines or adoptive lymphocyte transfer combined with chemotherapeutics. These therapies were effective against established tumors in animal models and showed promising results in initial clinical trials in cancer patients, awaiting testing in larger randomized controlled studies. Although combination between immunotherapy and chemotherapy has long been viewed as incompatible as chemotherapy, especially in high doses meant to increase anti-tumor efficacy, has induced immunosuppression, various mechanisms may explain the reported synergistic effects of the two types of therapies. Thus direct effects of chemotherapy on tumor or host environment, such as induction of tumor cell death, elimination of regulatory T cells, and/or enhancement of tumor cell sensitivity to lysis by CTL may account for enhancement of immunotherapy by chemotherapy. Furthermore, induction of lymphopenia by chemotherapy has increased the efficacy of adoptive lymphocyte transfer in cancer patients. On the other hand, immunotherapy may directly modulate the tumor's sensitivity to chemotherapy. Thus, anti-tumor mAb can increase the sensitivity of tumor cells to chemotherapeutic drugs and patients treated first with immunotherapy followed by chemotherapy showed higher clinical response rates than patients that had received chemotherapy alone. In conclusion, combination of active specific immunotherapy or adoptive mAb or lymphocyte immunotherapy with chemotherapy has great potential for the treatment of cancer patients which needs to be confirmed in larger controlled and randomized Phase III trials.

Immunohistological analysis of peptide-induced delayed-type hypersensitivity in advanced melanoma patients treated with melanoma antigen-pulsed mature monocyte-derived dendritic cell vaccination

BACKGROUND

In melanoma patients vaccinated with monocyte-derived melanoma peptide-pulsed dendritic cells (DC), the delayed-type hypersensitivity (DTH) reactions have been examined as a surrogate marker to determine if acquired immunity is induced by DC vaccination. To date, however, only limited information has been reported as for histopathological analyses of DTH.

OBJECTIVE

To evaluate tumor-specific immunomonitoring histopathologically after DC vaccination in melanoma patients.

METHODS

Seven patients previously vaccinated with monocyte-derived melanoma peptide-pulsed DCs were challenged with recall antigenic peptide injection in the skin of the forearm. Using immunohistochemical techniques, the presence of immune cells and the expression of CD4, CD8, interleukin (IL)-2, IL-4, IL-10, Foxp3, CD1a, CD1d, and interferon (IFN)-gamma was investigated at the site of injection where a DTH reaction developed.

RESULTS

Strong DTH reactions from infiltrated erythema to bullae formation were detected in all 7 cases. Biopsies taken from the DTH site revealed heavy infiltration of mononuclear cells and eosinophils in the dermis and subcutaneous tissue. Cells staining positively for CD4, CD8, IL-2, IL-4, Foxp3, CD1d, and IFN-gamma were increased at the site 48h after antigen injection in all cases. Cells positive for IL-10 were never found in any patient. Regulatory T cells appeared 6h after injection and reached their maximum at day 7.

CONCLUSIONS

The significant induction of CD8(+)T cells as well as both Th1 and Th2-type cells at the site of DTH suggests that effective antigen presentation leading to anti-tumor immune responses has taken place. Inhibitory mechanisms may also develop as the disappearance of the DTH response could be related to an increase in Foxp3+ cells.