3‐Methylcholanthrene‐induced transforming growth factor‐β‐producing carcinomas,but not sarcomas,are refractory to regulatory T cell‐depletion therapy

Regulatory T cells (Tregs) are major immunosuppressors in tumor‐bearing hosts. Although Treg‐depletion therapy has been shown to induce a complete cure in tumor‐bearing mice, this treatment is not always successful. Using 3‐methylcholanthrene‐induced primary mouse tumors, we examined the distinct regulation of Treg‐mediated immunosuppression between carcinomas and sarcomas. We showed that the number of Tregs was greatly increased in squamous cell carcinoma (SCC)‐bearing mice compared with sarcoma‐bearing mice. This appeared to be because SCC produced higher levels of active transforming growth factor (TGF)‐β, which is essential for inducing Tregs, compared with sarcoma. Moreover, SCC, but not sarcomas, were refractory to Treg‐depletion therapy by treatment with anti‐CD25 mAb. The refractoriness of SCC against Treg‐depletion therapy was due to the rapid recovery of Tregs in SCC‐bearing mice compared with sarcoma‐bearing mice. However, combination treatment of anti‐TGF‐β mAb with anti‐CD25 mAb caused a significant reduction in Treg recovery and induced a complete cure in SCC‐bearing mice. Thus, we showed the refractoriness of mouse carcinoma against Treg‐depletion therapy using anti‐CD25 mAb treatment. We also proposed a novel Treg‐blocking combination therapy using anti‐CD25 mAb and anti‐TGF‐β mAb to induce a complete cure of tumor‐bearing hosts. (Cancer Sci 2010; 101: 855–861)     

Necrosis in DU145 prostate cancer spheroids induces COX‐2/mPGES‐1‐derived PGE2 to promote tumor growth and to inhibit T cell activation

Cyclooxygenase (COX)‐2‐derived prostaglandin E2 (PGE₂) supports the growth of a spectrum of cancers. The potential benefit of COX‐2‐inhibiting non‐steroidal anti‐inflammatory drugs (NSAIDs) for cancer treatment is however limited by their well‐known cardiovascular side‐effects. Therefore, targeting microsomal PGE synthase 1 (mPGES‐1), the downstream enzyme in the COX‐2‐dependent pathway of PGE₂ production might be attractive, although conflicting data regarding a potential tumor‐supporting function of mPGES‐1 were reported. We determined the impact of mPGES‐1 in human DU145 prostate cancer cell growth. Surprisingly, knockdown of mPGES‐1 did not alter growth of DU145 monolayer cells, but efficiently inhibited the growth of DU145 multicellular tumor spheroids (MCTS). Opposed to MCTS, monolayer cells did not secrete PGE₂ due to a lack of COX‐2 expression, which was induced during spheroid formation. Pharmacological inhibition of COX‐2 and mPGES‐1 supported the crucial role of PGE₂ for growth of MCTS. The functionality of spheroid‐derived PGE₂ was demonstrated by its ability to inhibit cytotoxic T cell activation. When investigating mechanisms of spheroid‐induced COX‐2 induction, we observed that among microenvironmental factors neither glucose deprivation, hypoxia nor tumor cell apoptosis enhanced COX‐2 expression. Interestingly, interfering with apoptosis in spheroids triggered a shift towards necrosis, thus augmenting COX‐2 expression. We went on to demonstrate that necrotic cells induced COX‐2 mRNA expression and PGE₂ secretion from live tumor cells. In conclusion, necrosis‐dependent COX‐2 upregulation in MCTS promoted PGE₂‐dependent tumor growth and inhibited activated cytotoxic T cells. Hence, blocking mPGES‐1 as a therapeutic option may be considered for COX‐2/mPGES‐1‐positive solid cancers.     

FOXP3-positive regulatory T lymphocytes and epithelial FOXP3 expression in synchronous normal, ductal carcinoma in situ, and invasive cancer of the breast

FOXP3-expressing T regulatory lymphocytes (Tregs) have been described as putative mediators of immune tolerance, and thus facilitators of tumor growth. When found in association with various malignancies, Tregs are generally markers of poor clinical outcome. However, it is unknown whether they are also associated with cancer progression. We evaluated quantitative FOXP3 expression in lymphocytes as well as in epithelial cells in a set of thirty-two breast tumors with synchronous normal epithelium, ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC) components. Tumors were stained for FOXP3 and CD3 expression and Tregs quantified by determining the ratio of colocalized FOXP3 and CD3 relative to 1) total CD3-expressing lymphocytes and 2) to FOXP3-expressing epithelial cells. The median proportion of FOXP3-expressing CD3 cells significantly increased with malignant progression from normal to DCIS to IDC components (0.005, 0.019 and 0.030, respectively; p ≤ 0.0001 for normal vs. IDC and p = 0.004 for DCIS vs. IDC). The median intensity of epithelial FOXP3 expression was also increased with invasive progression and most markedly augmented between normal and DCIS components (0.130 vs. 0.175, p ≤ 0.0001). Both Treg infiltration and epithelial FOXP3 expression were higher in grade 3 vs. grade 1 tumors (p = 0.014 for Tregs, p = 0.038 for epithelial FOXP3), but did not vary significantly with hormone receptor status, size of invasive tumor, lymph node status, or disease stage. Notably, Treg infiltration significantly correlated with epithelial up-regulation of FOXP3 expression (p = 0.013 for normal, p = 0.001 for IDC). These findings implicate both Treg infiltration and up-regulated epithelial FOXP3 expression in breast cancer progression.     

Reactivation of hepatitis B virus after rituximab‐containing treatment in patients with CD20‐positive B‐cell lymphoma

BACKGROUND:

Reactivation of hepatitis B virus (HBV) after rituximab‐containing chemotherapy in patients with B‐cell lymphoma has been recognized as a potentially serious complication in HBV immune patients.

METHODS:

To determine the HBV reactivation in patients treated with rituximab, a retrospective study of HBV‐related markers was performed before and after rituximab‐containing treatment in 261 consecutive patients with CD20‐positive B‐cell lymphoma.

RESULTS:

Of the 261 patients, 230 patients were tested for both hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti‐HBc) before treatment. Fifty‐six (24.3%) of 230 patients were anti‐HBc positive, and the remaining 174 (75.6%) patients were anti‐HBc negative. Among the 56 anti‐HBc–positive patients, 5 (8.9%) became HBsAg positive (HBV reactivation), whereas none of the 174 anti‐HBc–negative patients became HBsAg positive with a median follow‐up of 24 months (P = .001). Among the 5 patients with HBV reactivation, 4 were negative for antibody to HBsAg (anti‐HBs), and 1 patient was positive for anti‐HBs. All 5 of these patients were treated successfully with entecavir on detection of HBsAg, although 4 of the 5 patients exhibited mild to moderate elevation of alanine aminotransferase. Among 56 anti‐HBc–positive patients, those negative for anti‐HBs had a higher probability of developing HBV reactivation compared with those positive for anti‐HBs (4 of 19; 21.1% vs 1 of 37; 2.7%, P = .014).

CONCLUSIONS:

Patients with isolated anti‐HBc are at high risk of HBV reactivation and should be monitored closely for HBsAg, anti‐HBs, HBV‐DNA, and transaminase levels during and after rituximab‐containing treatment. Although preemptive use of entecavir enabled successful management of HBV reactivation, mild to moderate hepatic flare was still observed. These approaches should be further evaluated in a prospective study with regard to clinical usefulness, safety, and cost‐effectiveness. Cancer 2010. © 2010 American Cancer Society.     

Suppression of Tregs by anti‐glucocorticoid induced TNF receptor antibody enhances the antitumor immunity of interferon‐α gene therapy for pancreatic cancer

We have reported that interferon (IFN)‐α can attack cancer cells by multiple antitumor mechanisms including the induction of direct cancer cell death and the enhancement of an immune response in several pancreatic cancer models. However, an immunotolerant microenvironment in the tumors is often responsible for the failure of the cancer immunotherapy. Here we examined whether the suppression of regulatory T cells (Tregs) within tumors can enhance an antitumor immunity induced by an intratumoral IFN‐α gene transfer. First we showed that an intraperitoneal administration of an agonistic anti‐glucocorticoid induced TNF receptor (GITR) monoclonal antibody (mAb), which is reported to suppress the function of Tregs, significantly inhibited subcutaneous tumor growth in a murine pancreatic cancer model. The anti‐GITR mAb was then combined with the intratumoral injection of the IFN‐α‐adenovirus vector. The treatment with the antibody synergistically augmented the antitumor effect of IFN‐α gene therapy not only in the vector‐injected tumors but also in the vector‐uninjected tumors. Immunostaining showed that the anti‐GITR mAb decreased Foxp3⁺ cells infiltrating in the tumors, while the intratumoral IFN‐α gene transfer increased CD4⁺ and CD8⁺ T cells in the tumors. Therefore, the combination therapy strongly inclined the immune balance of the tumor microenvironment in an antitumor direction, leading to a marked systemic antitumor effect. The CCR5 expression on Tregs was downregulated in the antibody‐treated mice, which may explain the decrease of tumor‐infiltrating Tregs. The combination of Treg‐suppression by GITR mAb and the tumor immunity induction by IFN‐α gene therapy could be a promising therapeutic strategy for pancreatic cancer.     

Stevens–Johnson Syndrome associated with mogamulizumab treatment of adult T‐cell leukemia / lymphoma

We report an adult T‐cell leukemia/lymphoma patient suffering from Stevens–Johnson Syndrome (SJS) during mogamulizumab (humanized anti‐CCR4 monoclonal antibody) treatment. There was a durable significant reduction of the CD4⁺CD25^highFOXP3⁺ regulatory T (Treg) cell subset in the patient's PBMC, and the affected inflamed skin almost completely lacked FOXP3‐positive cells. This implies an association between reduction of the Treg subset by mogamulizimab and occurrence of SJS. The present case should contribute not only to our understanding of human pathology resulting from therapeutic depletion of Treg cells, but also alert us to the possibility of immune‐related severe adverse events such as SJS when using mogamulizumab. We are currently conducting a clinical trial of mogamulizumab for CCR4‐negative solid cancers (UMIN000010050), specifically aiming to deplete Treg cells.     

Peritumoral FOXP3+ regulatory T cell is sensitive to chemotherapy while intratumoral FOXP3+ regulatory T cell is prognostic predictor of breast cancer patients

It has been reported that the prognostic significances of tumor-infiltrating FOXP3(+) regulatory T cells (Tregs) in breast carcinoma depend on their relative density and tissue locations. We here assessed the changes of Tregs before and after neoadjuvant chemotherapy (NC) and their relationships with tumor response and patient survival. Intratumoral and peritumoral infiltration of FOXP3(+) Tregs were evaluated by immunohistochemistry in 132 cases of invasive breast carcinomas before and after NC. After NC, the density of infiltrated Tregs within tumor bed remained stable, whereas it decreased significantly (P?=?0.015) in the tissue surrounding tumor. The changes were significant in those tumors that usually response to NC, including the HER2-enriched and basal-like subtypes (P?=?0.035; P?=?0.004). Univariate and multivariate analyses identified the decreased peritumoral Tregs were an independent predictor for pathologic complete response (pCR), while the intratumoral Tregs after chemotherapy was proved to be associated with overall survival and progression-free survival of the patients. The findings of the study indicated that peritumoral Treg was sensitive to chemotherapy and associated with pCR, while intratumoral Treg was an independent prognostic predictor of breast cancer patients.     

A selective cyclooxygenase‐2 inhibitor prevents inflammation‐related squamous cell carcinogenesis of the forestomach via duodenogastric reflux in rats

BACKGROUND:

Duodenal reflux causes inflammation‐related squamous cell carcinogenesis in the forestomach of rats without any carcinogens. The aim of this study was to investigate the efficacy of a selective cyclooxygenase (COX)‐2 inhibitor, meloxicam, in preventing this carcinogenesis.

METHODS:

A series of 188 rats underwent a surgical duodenogastric reflux procedure and were divided into 2 groups. One group was given commercial chow (control group), and the other was given experimental chow containing meloxicam (0.3 mg/kg body weight/day) (meloxicam group). The animals were sequentially sacrificed at Weeks 20, 30, 40, 50, and 60 after surgery. The forestomach was examined for the presence of carcinoma, the incidence of reflux‐related morphological changes, COX‐2 expression, and its activity.

RESULTS:

At Week 60, squamous cell carcinoma developed in 8 of 21 animals (38%) in the control group, but none of 20 (0%) in the meloxicam group (P < .05). In addition, basal cell dysplasia developed in 19 of 21 (90%) animals in the control group, but only 4 of 20 (20%) in the meloxicam group (P < .01). COX‐2 immunoreactivity was predominantly detected in macrophages in the epithelial stroma. Compared with nonsurgical rats, RNA expression of COX‐2 in the epithelium was up‐regulated, reaching peak at an early stage of Week 20 in both groups (P < .005). The expression of microsomal prostaglandin E synthase‐1 was lower in the meloxicam group than in the control group. PGE₂ production was significantly suppressed throughout the experiment in the meloxicam group compared with the control group (P < .005).

CONCLUSIONS:

Meloxicam was effective in preventing reflux‐induced squamous cell carcinogenesis via an inflamed squamous epithelium. Cancer 2009. © 2009 American Cancer Society.     

CD8⁺ cytotoxic T cell and FOXP3⁺ regulatory T cell infiltration in relation to breast cancer survival and molecular subtypes

The prognostic significance of tumor-associated FOXP3⁺ regulatory T cells (Tregs) and CD8⁺ cytotoxic T lymphocytes (CTLs) in invasive breast carcinomas is studied. Tregs and CTLs were assessed by immunohistochemistry in 1270 cases of invasive breast carcinoma for their associations with patient survival, histopathologic features, and molecular subtypes. Infiltrates of Tregs and CTLs were observed within tumor bed and in the tissue surrounding tumor. Within tumor bed, increased infiltration of Tregs and CTLs was significantly more common in those with unfavorable histologic features, including high histologic grade and negative ER and PR status. In addition, high density Treg infiltration was also associated with tumor HER2 overexpression, decreased overall survival (OS) and progression-free survival (PFS). In tissue surrounding tumor, in contrast, high CTL/Treg ratio was found to be significantly associated with improved OS and PFS. These prognostic associations were confirmed by multivariate analysis. Furthermore, the density of Treg infiltrates within tumors was inversely correlated with the prognosis of the molecular subtypes of tumors. The ratio of CTL/Treg infiltrates in the surrounding tissue was also significantly higher in luminal than non-luminal subtypes of carcinoma. The prognostic significances of Tregs and CTLs in breast carcinoma depend on their relative density and location. The density of intratumoral Treg infiltrates and the peritumoral CTL/Treg ratio are independent prognostic factors and correlated with the prognosis of the molecular subtypes of breast carcinoma, which may serve as potential target for stratifying immunotherapy to battle against the aggressive subtypes of breast carcinoma.     

Regulatory T cells are not a strong predictor of survival for patients with glioblastoma

Background

Regulatory T cells (Tregs) are potentially prognostic indicators in patients with glioblastoma. If differences in frequency of Tregs in tumor or blood account for substantial variation in patient survival, then reliably measuring Tregs may enhance treatment selection and improve outcomes.

Methods

We measured Tregs and CD3+ T cells in tumors and blood from 25 patients with newly diagnosed glioblastoma. Tumor-infiltrating Tregs and CD3+ T cells, measured by quantitative DNA demethylation analysis (epigenetic qPCR) and by immunohistochemistry, and peripheral blood Treg proportions measured by flow cytometry were correlated with patient survival. Additionally, we analyzed data from The Cancer Genome Atlas (TCGA) to correlate the expression of Treg markers with patient survival and glioblastoma subtypes.

Results

Tregs, as measured in tumor tissue and peripheral blood, did not correlate with patient survival. Although there was a correlation between tumor-infiltrating Tregs expression by epigenetic qPCR and immunohistochemistry, epigenetic qPCR was more sensitive and specific. Using data from TCGA, mRNA expression of Forkhead box protein 3 (FoxP3) and Helios and FoxP3 methylation level did not predict survival. While the classical glioblastoma subtype corresponded to lower expression of Treg markers, these markers did not predict survival in any of the glioblastoma subtypes.

Conclusions

Although immunosuppression is a hallmark of glioblastoma, Tregs as measured in tissue by gene expression, immunohistochemistry, or demethylation and Tregs in peripheral blood measured by flow cytometry do not predict survival of patients. Quantitative DNA demethylation analysis provides an objective, sensitive, and specific way of identifying Tregs and CD3+ T cells in glioblastoma.     

Prognostic impact of tumor infiltrating FOXP3 positive regulatory T cells in diffuse large B-cell lymphoma at diagnosis.

Tumor-infiltrating immune cells perform a crucial function in host immune reactions against diffuse large B-cell lymphoma (DLBCL). In this study, we have identified a subset of tumor-infiltrating FOXP3-positive regulatory T cells (Tregs) in the initial DLBCL biopsy specimens, and have evaluated their prognostic significance. Ninety six patients with DLBCL were evaluated retrospectively. The pattern of FOXP3 protein expression was evaluated using standard immunohistochemistry in paraffin-embedded tissue samples. Sixty seven of all 96 specimens were stained with antibodies for CD-10, bcl-6 and MUM1 via tissue microarray (TMA) to classify the cases into a germinal center B-cell like (GCB) group and a non-GCB group. The median overall survival (OS) was 28 months. As compared with the others, the patients with higher percentages of FOXP3-positive Tregs on initial tumor biopsy evidenced a significantly longer OS (p = 0.003). Patients classified into the GCB group evidenced a significantly longer OS as compared with the non-GCB group (p = 0.008). When the prognostic factors were evaluated via a multivariate model, the international prognostic index and the percentage of infiltrating FOXP3-positive Tregs in the initial biopsy were identified as independent predictors of OS. In conclusion, the presence of an increased percentage of FOXP3-positive Tregs in DLBCL is predictive of better prognoses.     

The VEGFR2, COX‐2 and MMP‐2 polymorphisms are associated with clinical outcome of patients with inoperable non‐small cell lung cancer

Certain common inherited variations in genes involved in tumor angiogenesis, progression and metastasis may contribute to cancer therapy outcome and prognosis by altering the gene expression and protein activity. In this report, we examined the effect of functional polymorphisms in MMP‐1, MMP‐2, MMP‐3, VEGF, VEGFR2, FGFR4 and COX‐2 genes on overall (OS) and progression‐free survival (PFS) of 350 Caucasian patients with inoperable non‐small cell lung cancer (NSCLC). The results of multivariate analysis indicated that VEGFR2 ‐906C and COX‐2 ‐1195G alleles were strongly associated with poor OS and PFS (p = 0.002 and 0.015, respectively, for OS; p = 0.009 and 0.015, respectively, for PFS), while MMP‐2 ‐1306 T allele carriers had significantly reduced PFS (p = 0.010). Moreover, an increased risk of death and progression was significantly associated with the number of adverse alleles for VEGFR2/COX‐2 (p = 0.0005 for OS and 0.0006 for PFS in >1 adverse allele carriers) and VEGFR2/COX‐2/MMP‐2 combinations (p = 0.0003 for OS and 0.0001 for PFS in patients with >2 adverse alleles). Finally, VEGFR2 TC/CC, COX‐2 AG/GG and MMP‐2 CT/TT genotypes as well as “at risk” allele combinations were identified as independent predictors of unfavorable OS and PFS in the group. In conclusion, the data suggest that selected VEGFR2, COX‐2 and MMP‐2 polymorphisms may be potential prognostic markers in unresectable NSCLC treated with radiotherapy with or without chemotherapy, although further validation studies are warranted to confirm our observations.     

Induction of human tumor‐associated differentially expressed gene‐12 (TADG‐12/TMPRSS3)‐specific cytotoxic T lymphocytes in human lymphocyte antigen‐A2.1–positive healthy donors and patients with advanced ovarian cancer

BACKGROUND:

Tumor‐associated differentially expressed gene‐12 (TADG‐12) is a serine protease recently found highly differentially expressed in epithelial ovarian cancer. The goal of this study was to identify potential immunogenic peptides derived from TADG‐12 for immunotherapy of ovarian carcinoma.

METHODS:

A bioinformatics approach (ie, the BIMAS algorithm, National Institutes of Health, http://bimas.dcrt.nih.gov/molbio/hla_bind ) was used to identify multiple immunogenic peptides derived from TADG‐12 that bind to human leukocyte antigen‐A2.1 and elicit peptide‐specific human cytotoxic T lymphocyte (CTL) responses in healthy individuals and in patients with advanced stage ovarian cancer.

RESULTS:

CD8+ CTL populations generated against 5 TADG‐12–derived peptides were consistently able to induce lysis of autologous peptide‐loaded target cells above background. Importantly, TADG‐12 YLPKSWTIQV peptide‐specific CTLs from healthy donors and ovarian cancer patients were found to effectively kill ovarian cancer cells naturally expressing TADG‐12. Cytotoxicity was significantly inhibited by anti–human lymphocyte antigen (HLA)‐A2.1 (BB7‐2) and anti–HLA class I (W6 of 32) monoclonal antibodies, whereas natural killer–sensitive K562 cells were not lysed. TADG‐12 YLPKSWTIQV peptide‐specific CTL precursor frequency was low in peripheral blood leukocytes of normal donors and ovarian cancer patients, as determined by interferon‐γ production in enzyme‐linked immunosorbent spot‐forming cell assays. Intracellular cytokine expression measured by flow cytometry after OKT‐3 monoclonal antibody stimulation showed a type 1 cytokine profile in YLPKSWTIQV peptide‐specific CTLs.

CONCLUSIONS:

The TADG‐12 YLPKSWTIQV peptide is an immunogenic epitope in ovarian tumors and may represent an attractive target for immunotherapy of ovarian cancer. These data may pave the way for TADG‐12 peptide‐derived cell‐based therapy, including dendritic cell immunotherapy, for the vaccination of ovarian cancer patients harboring chemotherapy‐resistant or residual disease. Cancer 2009. © 2008 American Cancer Society.     

Resistance of uveal melanoma to the interstrand cross-linking agent mitomycin C is associated with reduced expression of CYP450R

Background:

Uveal melanoma (UM) is the most common primary intraocular tumour of adults, frequently metastasising to the liver. Hepatic metastases are difficult to treat and are mainly unresponsive to chemotherapy. To investigate why UM are so chemo-resistant we explored the effect of interstrand cross-linking agents mitomycin C (MMC) and cisplatin in comparison with hydroxyurea (HU).

Methods:

Sensitivity to MMC, cisplatin and HU was tested in established UM cell lines using clonogenic assays. The response of UM to MMC was confirmed in MTT assays using short-term cultures of primary UM. The expression of cytochrome P450 reductase (CYP450R) was analysed by western blotting, and DNA cross-linking was assessed using COMET analysis supported by γ-H2AX foci formation.

Results:

Both established cell lines and primary cultures of UM were resistant to the cross-linking agent MMC (in each case P<0.001 in Student''s t-test compared with controls). In two established UM cell lines, DNA cross-link damage was not induced by MMC (in both cases P<0.05 in Students''s t-test compared with damage induced in controls). In all, 6 out of 6 UMs tested displayed reduced expression of the metabolising enzyme CYP450R and transient expression of CYP450R increased MMC sensitivity of UM.

Conclusion:

We suggest that reduced expression of CYP450R is responsible for MMC resistance of UM, through a lack of bioactivation, which can be reversed by complementing UM cell lines with CYP450R.     

Skewed immunological balance between Th17 (CD4+IL17A+) and Treg (CD4+CD25+FOXP3+) cells in human oral squamous cell carcinoma

Background

Several studies have documented modulation of Th17 and T regulatory (Treg) cells in various human malignancies which may vary with the type and extent of the disease. However, such data in patients with oral cancer is scarce and hence the current study was designed to elaborate the immunological balance between these two T cell subsets in oral cancer.

Methods and results

We analyzed various T cell subsets in the peripheral blood of 45 oral squamous cell carcinoma (OSCC) patients and 40 healthy volunteers. We found that, compared with the healthy controls, patients had a significantly (p?<?0.0001) higher proportion of both Th17 (CD4⁺IL17A⁺) and Treg (CD4⁺CD25⁺FOXP3⁺) cells, which further showed a reciprocal balance in relation to clinico-pathological parameters in patients. We also detected a circulating CD8⁺ subset of these cells in both patients and healthy controls, although the difference between the two groups was statistically insignificant. Higher frequencies of Th17 cells were found in patients with early stages and without lymph node involvement, while an increased prevalence of Tregs was associated with higher clinical stages and lymph node involvement. Moreover, Th17 cells were quantitatively and positively correlated to CD4⁺T and CD8⁺T cells and inversely correlated with Tregs. Contrarily, Tregs showed a negative association with CD4⁺T and CD8⁺T cells.

Conclusions

Our results suggest an increase in Th17/Tregs ratio in early stages and a decrease in this ratio in higher stages of oral cancer. Such counter regulation of Th17 and Tregs may be a significant prognostic factor in oral cancer patients.