Prognostic Impact of FoxP3+ Regulatory T Cells in Relation to CD8+ T Lymphocyte Density in Human Colon Carcinomas

<div><h3>Background</h3><p>T-lymphocyte infiltration into colon carcinomas can influence clinical outcome, and interactions among T cell subsets may be more informative than either subset alone. Our objective was to examine the prognostic impact of tumor-infiltrating FoxP3⁺ regulatory T cells (Tregs) in relation to cytotoxic CD8⁺ T lymphocytes in patients with colon carcinomas characterized by DNA mismatch repair (MMR) status who participated in adjuvant chemotherapy trials.</p> <h3>Methods</h3><p>FoxP3⁺ and CD8⁺ densities in tumor epithelial and stromal compartments were analyzed by immunohistochemistry and quantified in resected, stage II and III colonic carcinomas (N = 216). Immune marker density was dichotomized at the median and categorized as high <em>vs</em> low. MMR status was classified as MMR deficient (dMMR) or proficient (pMMR). Cox models were adjusted for age, stage, and tumor grade.</p> <h3>Results</h3><p>The density of FoxP3+ infiltration was similar in tumor stroma and epithelia, whereas CD8+ was higher in stroma. The prognostic impact of FoxP3+ and CD8+ T cell infiltration was stronger in stroma <em>vs</em> epithelia, and the density of each marker in stroma was independently associated with improved overall survival (OS). However, the impact of FoxP3+ on survival was dependent upon CD8+ density (<em>P</em> interaction  = .040). Among CD8+_low tumors, FoxP3+_high cases had significantly improved OS compared to FoxP3+_low cases after adjustment for covariates (hazard ratio 0.43; 95% confidence interval 0.19 to 0.95; P = .030). In contrast, FoxP3+ was not prognostic among CD8+_high tumors. FoxP3+ remained prognostic in CD8+_low tumors after further adjustment for MMR or <em>BRAF</em>^V600E mutation status. Additionally, these immune markers identified a pMMR subgroup with a similarly favorable OS as for dMMR tumors.</p> <h3>Conclusions</h3><p>The prognostic impact of FoxP3+ and CD8+ T cell density are inter-dependent, whereby FoxP3+ exerts a favorable influence on survival only in colon cancers with low CD8+ infiltration.</p> </div

Multivariable Cox Models for Overall Survival Examining CD8+ and FoxP3+ T-cell Density^a.

a<p>Each model is adjusted for age, stage, grade.</p>b<p>CD8+ and FoxP3+ densities were dichotomized at the median.</p><p>Abbreviations: MMR, mismatch repair.</p

Immune marker expression in colon carcinomas.

<p>Expression of FoxP3+ (a) and cytotoxic CD8+ (b) proteins in T lymphocytes, determined by immunohistochemistry, is shown infiltrating the tumor stroma and epithelia of resected colon carcinomas (<i>left</i>, 20× objective; <i>right</i>, 40× objective).</p

Patient survival according to CD8+ and FoxP3+ T-cell density.

<p>Overall survival (OS) in resected colon carcinomas with (a) high <i>vs</i> (b) low density of cytotoxic CD8+ T-cell infiltration in tumor stroma according to FoxP3+ T-cell density in tumor stroma (<i>P</i> for interaction  = .040). Hazard ratios (HR) are adjusted for age, stage, and tumor grade.</p

Patient survival and comparison of clinicopathologic variables by MMR status and T-cell density.

<p>Overall survival (OS) in deficient MMR (dMMR) <i>vs</i> proficient MMR (pMMR) colon carcinomas according to the density of FoxP3+ (a) or CD8+ (b) T lymphocytes in tumor stroma, showing similar OS among cases with dMMR <i>vs</i> pMMR with high densities of CD8+ or FoxP3+. Comparison of clinicopathological variables (c) between dMMR <i>vs</i> CD8+_high or FoxP3+_high pMMR cancers demonstrates differences in histologic grade and tumor site. Grade: 1 or 2, well- or moderately differentiated; 3 or 4, poor or undifferentiated.</p

Clinicopathologic Characteristics of Study Population by Immune Marker Density (N = 216).

a<p>T cell densities were dichotomized at the median.</p>b<p>FoxP3+ (N = 156).</p>c<p>Histologic Grade: 1 or 2, well or moderately differentiated; 3 or 4, poor or undifferentiated.</p

Multivariable Cox Models for Overall Survival Examining Stromal FoxP3+ T-cell Density Stratified by CD8+ T-cell Density^a.

a<p>CD8+ and FoxP3+ densities were dichotomized at the median.</p>b<p>pMMR (N = 119).</p>c<p>Within each model, hazard ratios and p values are adjusted for all variables shown.</p

Gemcitabine and Irinotecan as First-Line Therapy for Carcinoma of Unknown Primary: Results of a Multicenter Phase II Trial

<div><p>Metastatic carcinoma of unknown primary (CUP) has a very poor prognosis, and no standard first-line therapy currently exists. Here, we report the results of a phase II study utilizing a combination of gemcitabine and irinotecan as first-line therapy. Treatment was with gemcitabine 1000 mg/m² and irinotecan 75 mg/m² weekly times four on a six week cycle (Cohort I). Due to excessive toxicity, the dose and schedule were modified as follows: gemcitabine 750 mg/m² and irinotecan 75 mg/m² given weekly times three on a four week cycle (Cohort II). The primary endpoint was the confirmed response rate (CR + PR). Secondary endpoints consisted of adverse events based upon the presence or absence of the UDP glucuronosyltransferase 1 family, polypeptide A1*28 (UGT1A1*28) polymorphism, time to progression, and overall survival. Thirty-one patients were enrolled with a median age of 63 (range: 38–94), and 26 patients were evaluable for efficacy. Significant toxicity was observed in Cohort 1, characterized by 50% (7/14) patients experiencing a grade 4+ adverse event, but not in cohort II. The confirmed response rate including patients from both cohorts was 12% (95% CI: 2–30%), which did not meet the criteria for continued enrollment. Overall median survival was 7.2 months (95% CI: 4.0 to 11.6) for the entire cohort but notably longer in cohort II than in cohort I (9.3 months (95% CI: 4.1 to 12.1) versus 4.0 months (95% CI: 2.2 to 15.6)). Gemcitabine and irinotecan is not an active combination when used as first line therapy in patients with metastatic carcinoma of unknown primary. Efforts into developing novel diagnostic and therapeutic approaches remain important for improving the outlook for this heterogeneous group of patients.</p> <h3>Trial Registration</h3><p>ClinicalTrials.gov <a href="http://clinicaltrials.gov/ct2/show/NCT00066781">NCT00066781</a></p> </div

CONSORT diagram.

<p>CONSORT diagram.</p

Patient Characteristics.

<p>Patient Characteristics.</p