Immunological effects of nivolumab immunotherapy in patients with oral cavity squamous cell carcinoma.

BACKGROUND: Although checkpoint blockades have become widely used, the immunological impact in cancer patients, especially those with oral cavity squamous cell carcinoma (OCSCC), has not been well studied. METHODS: The present study assessed the immunological impact of anti-PD-1 (nivolumab) treatment in 10 patients with OCSCC. This involved phenotypic analyses of peripheral blood T-cell subpopulations and their expression of immune mediators prior to and following nivolumab treatment. The focus was on immunological effects of treatment without regard to possible clinical responses. RESULTS: Nivolumab caused a decline in the frequency of blood CD4+ cells but did not affect their expression of IFN-γ. However, nivolumab increased the proportion of CD4+ cells expressing the Treg-supporting factor Foxp3. Nivolumab treatment caused an increase in the proportion of CD8+ cells. While their expression of granzyme B increased, it did not attain significance. Analyses of CD8+ cell subpopulations showed nivolumab caused an increase in levels of unconventional CD8dimCD3+ T-cells. It also caused an increase in expression of granzyme B by these unconventional T-cells as well as by the conventional CD8hiCD3+ cells. The CD8hiCD3+ subpopulation also had a near-significant increase in IFN-γ expression. Treatment with nivolumab had no effect on the levels of the NK containing CD8dimCD3- subpopulation of cells or their expression of IFN-γ or granzyme B. CONCLUSIONS: These results show nivolumab causes opposing effects on CD4+ and CD8+ cell populations, with CD4+ cell levels declining but increasing the proportion of Treg cells, and unconventional CD8+ T-cell levels increasing with increased expression of immune mediators by CD8+ T-cell subpopulations.

High-Fat Diet Alters Immunogenic Properties of Circulating and Adipose Tissue-Associated Myeloid-Derived CD45+DDR2+ Cells.

Chronic inflammation is evident in the adipose tissue and periphery of patients with obesity, as well as mouse models of obesity. T cell subsets in obese adipose tissue are skewed towards Th1- and Th17-associated phenotypes and their secreted cytokines contribute to obesity-associated inflammation. Our lab recently identified a novel, myeloid-derived CD45+DDR2+ cell subset that modulates T cell activity. The current study sought to determine how these myeloid-derived CD45+DDR2+ cells are altered in the adipose tissue and peripheral blood of preobese mice and how this population modulates T cell activity. C57BL/6 mice were fed with a diet high in milkfat (60%·kcal, HFD) ad libitum until a 20% increase in total body weight was reached, and myeloid-derived CD45+DDR2+ cells and CD4+ T cells in visceral adipose tissue (VAT), mammary gland-associated adipose tissue (MGAT), and peripheral blood (PB) were phenotypically analyzed. Also analyzed was whether mediators from MGAT-primed myeloid-derived CD45+DDR2+ cells stimulate normal CD4+ T cell cytokine production. A higher percentage of myeloid-derived CD45+DDR2+ cells expressed the activation markers MHC II and CD80 in both VAT and MGAT of preobese mice. CD4+ T cells were preferentially skewed towards Th1- and Th17-associated phenotypes in the adipose tissue and periphery of preobese mice. In vitro, MGAT from HFD-fed mice triggered myeloid-derived CD45+DDR2+ cells to induce CD4+ T cell IFN-γ and TNF-α production. Taken together, this study shows that myeloid-derived CD45+DDR2+ cells express markers of immune activation and suggests that they play an immune modulatory role in the adipose tissue of preobese mice.

Transient immunological and clinical effectiveness of treating mice bearing premalignant oral lesions with PD-1 antibodies.

A carcinogen-induced premalignant oral lesion model that progresses to oral cancer was used to examine the impact of blocking PD-1 on cytokine expression and on progression of lesions to cancer. The results of this study show increased production of IL-2 and the inflammatory cytokines IL-6, IL-17 and TNF-α by spleen cells of lesion-bearing mice that were treated with PD-1 antibody for 1 week compared to cytokine production by spleen cells of lesion-bearing mice treated with control antibody. Production of IFN-γ increased at 3 weeks of PD-1 antibody treatment, although production of the other Th1 and inflammatory mediators declined. By 5 weeks, levels of these cytokines declined for both control and PD-1 antibody-treated mice. Flow cytometric analysis for IFN-γ-expressing cells showed shifts in CD4+ cells expressing IFN-γ consistent with the changes in cytokine secretion. Whether or not treatment generated reactivity to lesions or HNSCC was determined. Spleen cells from PD-1 antibody-treated mice were stimulated by lysates of premalignant lesion and HNSCC tongue tissues to produce increased levels of Th1 and select inflammatory cytokines early in the course of PD-1 antibody treatment. However, with continued treatment, reactivity to lesion and HNSCC lysates declined. Analysis of clinical response to treatment suggested an early delay in lesion progression but, with continued treatment, lesions in PD-1 antibody-treated mice progressed to the same degree as in control antibody-treated mice. Overall, these results show an early beneficial response to PD-1 antibody treatment, which then fails with continued treatment and lesion progression.

Cancer Immunology with a Focus on Understudied Cancers as Targets for Immunotherapy.

n/a.

Treatment to sustain a Th17-type phenotype to prevent skewing toward Treg and to limit premalignant lesion progression to cancer.

While immune suppression is a hallmark of head and neck squamous cell carcinoma (HSNCC), the immunological impact of premalignant oral lesions, which often precedes development of HNSCC, is unknown. The present study assessed the changes in splenic and draining lymph node CD4(+) cell populations and their production of select cytokines that occur in mice with carcinogen-induced premalignant oral lesions and the changes that occur as lesions progress to oral cancer. These studies found skewing toward Th1 and Th17-type phenotypes in the spleen and lymph nodes of mice with premalignant oral lesions and a shift to Treg as lesions progress to cancer. Since the role of Th17 cells in the progression from premalignant lesions to cancer is not clear, studies determined the immunological and clinical effect of treating mice bearing premalignant oral lesions with a TGF-ß type 1 receptor inhibitor plus IL-23 as an approach to sustain the Th17 phenotype. These studies showed that the treatment approach not only sustained the Th17 phenotype, but also increased distal spleen cell and regional lymph node cell production of other stimulatory/inflammatory mediators and slowed premalignant lesion progression to cancer.

Restoration of Immune Responsiveness to Glioma by Vaccination of Mice with Established Brain Gliomas with a Semi-Allogeneic Vaccine.

Prior studies had shown the clinical efficacy of a semi-allogeneic glioma vaccine in mice with lethal GL261 gliomas. This was confirmed in the present study. As subcutaneous vaccination resulted in protection against tumor in the brain, the present study assessed the impact of this vaccination of mice bearing established GL261 brain gliomas on their cytokine production upon in vitro exposure to tumor-derived products. Mice with established GL261 brain gliomas were vaccinated subcutaneously with H-2(b) GL261 glioma cells fused with H-2(d) RAG-neo cells or with a mock vaccine of phosphate-buffered saline. The results of these analyses show that the presence of GL261 tumor-conditioned medium resulted in increased production of Th1, inflammatory and inhibitory cytokines by spleen cells from control mice and from vaccinated glioma-bearing mice. In contrast, spleen cells of tumor-bearing, mock-vaccinated mice produced lower levels of cytokines in the presence of tumor-conditioned media. However, these results also show that there was not a heightened level of cytokine production in the presence of tumor-conditioned medium by spleen cells of vaccinated mice over the production by spleen cells of control mice. Overall, these results show that vaccination slows growth of the GL261 tumors to the point where GL261-vaccinated mice do not show the signs of morbidly or splenic dysfunction exhibited by unvaccinated, late stage glioma-bearing mice.

Characterization of the evolution of immune phenotype during the development and progression of squamous cell carcinoma of the head and neck.

While studies have indicated that squamous cell carcinoma of the head and neck (HNSCC) is associated with immune suppression, these studies did not analyze the immune response at the dysplastic stage. The present study utilized a mouse model of 4-nitroquinoline 1-oxide-induced oral carcinogenesis to examine the alterations in immune phenotype at the premalignant and malignant stages of HNSCC. Cervical lymph nodes of HNSCC-bearing mice were found to contain a greater number of cells, including a greater number of conventional (Tconv) and regulatory (Treg) T cells, compared to cervical lymph nodes of control and premalignant lesion-bearing mice, though the Tconv cells appear to be less proliferative and the Treg cells appear to be less suppressive at the HNSCC stage. Premalignant lesion-bearing mouse lymph nodes consist of a greater percentage of Tconv cells expressing markers for activation, memory, and exhaustion compared to both control and HNSCC-bearing mice. Also, lymph nodes' cells from both premalignant lesion-bearing and HNSCC-bearing mice include increased levels of Th1, Tc1, and Th17 cells, with no differences in levels of Th2 cells, compared to control mice. The data show that while there is the expected increase in immunosuppressive Tregs in lymph nodes when HNSCC is present, there is also an unexpected increase in immune populations usually associated with a beneficial antitumor response, including Tconv cells and Th1 and Tc1 cells. In addition, the results demonstrate that the premalignant stage of HNSCC development is associated with a robust immune response involving an increase in inflammatory Th1, Tc1, and Th17 cells.

Immunological modulation by 1α,25-dihydroxyvitamin D3 in patients with squamous cell carcinoma of the head and neck.

Prior studies showing that treatment of head and neck squamous cell carcinoma (HNSCC) patients with 1α,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] stimulated intratumoral immune infiltration were extended to analysis of cytokine profiles in the periphery and in oral tissues. Most prominent was the disparity between cytokine levels in plasma and in either pathologically normal oral tissue or HNSCC tissue from patients that were untreated or treated with 1,25(OH)(2)D(3). Levels of IL-6 and IL-10, but not IL-2, IFN-γ or TNF-α, tended to be increased in the plasma of HNSCC patients and 1,25(OH)(2)D(3) further increased plasma levels of all of these cytokines. While these cytokines tended to be increased in HNSCC tissue, 1,25(OH)(2)D(3) resulted in variable cytokine responses that showed a general tendency toward further increased levels. Levels of IL-8 and VEGF were increased in plasma and tissue of untreated HNSCC patients, and were further increased in plasma, but not in tissues, of patients treated with 1,25(OH)(2)D(3). Levels of IL-1α and IL-1ß were similar in plasma of controls and HNSCC patients, but were increased in HNSCC tissues. In contrast to that seen in plasma where 1,25(OH)(2)D(3) increased levels of IL-1α and IL-1ß, this was not seen in tissue following 1,25(OH)(2)D(3) treatment. These results show a discordant relationship between systemic and intratumoral cytokine profiles and suggest a tendency of 1,25(OH)(2)D(3)to increase a multitude of cytokines within tumor tissue.

Immunotherapy for head and neck cancer: advances and deficiencies.

The concept of immunotherapy as a treatment for cancer patients has been in existence for decades. However, more recent immune therapeutic approaches have involved targeting of tumor-specific antigens. Although improvements have been made in using such immune stimulatory treatment strategies for a variety of solid cancers, the use of these strategies for patients with head and neck squamous cell carcinoma (HNSCC) is lagging behind. Immunotherapeutic approaches for HNSCC are particularly complicated by the profound immune suppression that is induced by HNSCC, which potentially decreases the effectiveness of immune stimulatory efforts. Trials involving patients with various solid cancers have shown the enhanced effectiveness of combining various immunotherapeutic approaches or combining immunotherapy with chemotherapy or radiation therapy. Treatment of HNSCC with such combination approaches has not been extensively investigated and has the added challenge of the need to overcome the HNSCC-induced immune suppression. This study focuses on clinical trials that have tested immunotherapeutic approaches for HNSCC patients and the challenges associated with such approaches. In addition, it will call attention to immunotherapeutic strategies that have been shown to be successful in the treatment of other solid cancers to identify potential strategies that may apply to the treatment of HNSCC.

Regulatory T-cell trafficking: from thymic development to tumor-induced immune suppression.

Regulatory T cells (Tregs) have become a priority for many investigators in immunology due to their potent immunosuppressive and tolerogenic effects. While Treg activity is required for normal immune homeostasis, dysregulation of their numbers can induce autoimmunity or aid in the pathogenesis of disease. Therefore, great effort has been made to understand the mechanisms by which Tregs accumulate in different areas of the body. Like other lymphocytes, Tregs migrate in response to a network of chemotactic stimuli involving chemokines, chemokine receptors, integrins, and their corresponding ligands. However, many of these stimuli are exclusive to Tregs, inducing their migration while leaving conventional populations unaffected. It is these selective stimuli that result in increased ratios of Tregs among conventional effector populations, leading to changes in immune suppression and homeostasis. This review explores selective Treg trafficking during thymic Treg development, migration to secondary lymphoid tissues and emigration into the periphery during homeostatic conditions, inflammation, and the tumor microenvironment, placing emphasis on stimuli that selectively recruits Tregs to target locations.

NK-dependent increases in CCL22 secretion selectively recruits regulatory T cells to the tumor microenvironment.

Tumor-induced immune suppression involves the accumulation of immune-suppressive infiltrates in the microenvironment. This study demonstrates increased numbers of CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) in the lungs of C57BL/6 mice bearing a metastatic Lewis lung carcinoma (LLC) variant. These Tregs suppressed the proliferation of endogenous CD4(+)CD25(-) cells and expressed higher levels of the chemokine receptor CCR4 than other types of T cells. LLC-bearing lungs secreted elevated levels of the CCR4-associated chemokine CCL22 compared with normal lungs. However, CCL22 was not secreted by LLC or normal epithelial controls, suggesting that CCL22 is secreted by a nonepithelial component of the microenvironment. Migration assays revealed that medium conditioned by LLC-bearing lungs selectively recruited Tregs at higher frequencies than did medium conditioned by normal lungs. Neutralization of CCL22 significantly reduced this selective recruitment toward both conditioned media. A series of immunomagnetic isolations, FACS, and flow cytometric analyses were used to isolate different cellular fractions from both normal and LLC-bearing lungs. When isolated, only the NK-containing fractions secreted CCL22, and the same fraction isolated from LLC-bearing lungs secreted higher levels. Depletion of NK cells from both normal and LLC-bearing lung tissue significantly reduced CCL22 secretion, suggesting that a large portion of secreted CCL22 is NK cell dependent. Flow cytometric analysis of the lung NK compartments revealed no significant increase in NK cell numbers across LLC-bearing lung tissue as a whole as compared with normal tissue. However, immunofluorescent staining revealed an increased frequency of NK cells at the tumor periphery that were closely associated with the elevated FoxP3(+) infiltrate.

Neoadjuvant presurgical PD-1 inhibition in oral cavity squamous cell carcinoma.

Oral cavity squamous cell carcinoma (OCSCC) is a prevalent surgically treated subset of head and neck cancer with frequent recurrence and poor survival. Immunotherapy has demonstrated efficacy in recurrent/metastatic head and neck cancer. However, whether antitumor responses could be fostered by neoadjuvant presurgical immunotherapy remains unclear. Using a Simon's two-stage design, we present results of a single-arm phase-II trial where 12 patients with stage II-IVA OCSCC received 3 to 4 biweekly doses of 3 mg/kg nivolumab followed by definitive surgical resection with curative intent. Presurgical nivolumab therapy in this cohort shows an overall response rate of 33% (n = 4 patients; 95% CI: 12%-53%). With a median follow up of 2.23 years, 10 out of 12 treated patients remain alive. Neoadjuvant nivolumab is safe, well-tolerated, and is not associated with delays in definitive surgical treatment in this study. This work demonstrates feasibility and safety for incorporation of nivolumab in the neoadjuvant setting for OCSCC (ClinicalTrials.gov: NCT03021993).

NK depletion results in increased CCL22 secretion and Treg levels in Lewis lung carcinoma via the accumulation of CCL22-secreting CD11b+CD11c+ cells.

Tumor-induced immune suppression involves the accumulation of suppressive infiltrates in the tumor microenvironment such as regulatory T-cells (Tregs). Previous studies demonstrated that NK-dependant increases in CCL22 secretion selectively recruit Tregs toward murine lungs bearing Lewis Lung Carcinoma (LLC). To extend the in vitro studies, the present studies utilized in vivo depletion of NK cells to ascertain the contribution of NK-derived CCL22 toward total CCL22 and subsequent Treg levels in both normal and LLC-bearing lungs. However, NK depletion had the unexpected effect of increasing both CCL22 secretion and Treg levels in the lungs of NK-depleted LLC-bearing mice. This was concurrent with an increase in tumor burden. Flow cytometry and a series of both immunomagnetic and FACS isolations were used to identify the CCL22-producing cellular fractions in LLC-bearing lungs. A novel CD11b(+)CD11c(+) cell population was identified that accumulates in large numbers in NK-depleted LLC-bearing lung tissue. These CD11b(+)CD11c(+) cells secreted large amounts of CCL22 that may overcompensate for the loss of NK-derived CCL22 in the lungs of NK-depleted LLC-bearing mice. Taken together, these data suggest that NK cells play both a positive and negative role in the regulation of CCL22 secretion and, in turn, the recruitment of Tregs toward LLC-bearing lungs.

Tumors induce the formation of suppressor endothelial cells in vivo.

Patients with solid tumors have defects in immune effector cells, which have been associated with a poorer prognosis. Previous studies by our laboratory have shown that exposure to Lewis lung carcinoma (LLC)- secreted products induces the formation of suppressor endothelial cells in vitro. The current studies examined if tumors could induce the formation of suppressor endothelial cells in vivo. Endothelial cells were immunomagnetically isolated from the lungs of tumor-bearing mice or normal controls and examined for their ability to modulate NK cell, T-cell and macrophage functions. Compared to normal controls, supernatants from endothelial cells isolated from tumor-bearing lungs had elevated secretion of PGE2, IL-6, IL-10 and VEGF. Conditioned media from endothelial cells isolated from normal lungs increased CD8+ T-cell IFN-γ and CD4+ T-cell IL-2 production in response to anti-CD3 stimulation, while media conditioned by endothelial cells from tumor-bearing lungs had a diminished stimulatory capacity. Examination of NK cell functions showed that supernatants from endothelial cells isolated from normal lungs were potent activators of NK cells, as indicated by their secretion of TNF- and IFN-γ. Endothelial cells isolated from tumor-bearing lungs had a significantly diminished capacity to activate NK cells. Finally, supernatants from endothelial cells of tumor-bearing lungs diminished macrophage phagocytosis compared to either treatment with supernatants of normal endothelial cells or treatment with media alone. The results of these studies demonstrate that tumors induce the formation of suppressor endothelial cells in vivo and provide support for the role of endothelial cells in tumor-induced immune suppression.

1alpha,25-Dihydroxyvitamin D(3) to skew intratumoral levels of immune inhibitory CD34(+) progenitor cells into dendritic cells.

OBJECTIVES: Prior studies showed that immune inhibitory CD34(+) progenitor cells, whose numbers are increased in head and neck squamous cell carcinoma (HNSCC) patients, can be differentiated into immune stimulatory dendritic cells by culture with 1alpha,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3)). This was extended to a pilot study to diminish intratumoral levels of CD34(+) progenitor cells by inducing their maturation into dendritic cells with 1,25(OH)(2)D(3). STUDY DESIGN: Newly diagnosed HNSCC patients were untreated for 3 weeks or received 3 weeks of 1,25(OH)(2)D(3) treatment befoer surgical treatment. SUBJECTS AND METHODS: HNSCC tissue was collected by biopsy from six patients who had no prior 1,25(OH)(2)D(3) treatment and at the time of surgical treatment from six untreated patients and 11 patients who completed 1,25(OH)(2)D(3) treatment. Tissues were analyzed by immunohistochemistry for levels of CD34(+) cells and dendritic cells. RESULTS: After 1,25(OH)(2)D(3) treatment, intratumoral levels of CD34(+) cells and levels of immature dendritic cells declined. However, levels of intratumoral mature dendritic cells increased. Clinical effects of 1,25(OH)(2)D(3) treatment are premature to analyze. CONCLUSIONS: Treatment of HNSCC patients with 1,25(OH)(2)D(3) reduced levels of immune inhibitory CD34(+) cells while increasing maturation of dendritic cells. This supports added studies to determine the effect of 1,25(OH)(2)D(3) on intratumoral immune competence.

Reduced Expression of Immune Mediators by T-Cell Subpopulations of Combat-Exposed Veterans With Post-Traumatic Stress Disorder.

Post-traumatic stress disorder (PTSD) has been suggested to be associated with an inflammatory immune state, although few studies have examined peripheral blood lymphocytes in subjects that have PTSD and compared immune parameters to subjects that experienced similar trauma, but did not develop PTSD. An exploratory approach was undertaken to compare phenotypes of blood CD4+ and CD8+ subpopulations and their expression of immune mediators between Veterans of the Iraq and Afghanistan wars who experienced similar levels of combat, with some developing PTSD and other not. The results of this study did not demonstrate evidence of enhanced immune activation of peripheral blood lymphocytes. Instead, the results showed a decline in expression of the pro-inflammatory mediator IFN-γ and the cytotoxin granzyme B in CD8+ subpopulations from Veterans with PTSD. While the reductions in expression of IFN-γ and granzyme B did not reach statistical significance when examining the CD8+ cell population as a whole, the declines were significant when examining the CD8+ cell subpopulations, with different mediators being reduced in different subpopulations. The most prominent decline in IFN-γ expression was by the unconventional CD8dimCD3+ T-cell subpopulation that has been associated with chronic infection and immune fatigue. The decline in granzyme B was most prominent in the NK-containing CD8dimCD3- subpopulation of Tcells. Consequently, analysis of blood leukocyte subpopulations, rather than bulk lymphocyte groups, reveals a dampened level of immune reactivity in combat-exposed Veterans with PTSD compared to combat-exposed Veterans without PTSD.

Influence of vitamin D on cancer risk and treatment: Why the variability?

The association between vitamin D and cancer has long been studied, but the results have been variable. Thus, there does not seem to be a consensus on whether vitamin D has a beneficial anti-cancer effect. This review not only summarizes the association between vitamin D and cancer risk and results of clinical trials involving vitamin D, but explores some of the reasons that contribute to the variability of study outcomes. Highlighted are single nucleotide polymorphisms (SNPs) that contribute to variability in the efficacy of vitamin D supplementation. Understanding these differences can personalize approaches to optimize the effectiveness of vitamin D in limiting cancer risk.

Role of IL-23 signaling in the progression of premalignant oral lesions to cancer.

Mice bearing carcinogen-induced premalignant oral lesions were previously shown to have a pro-inflammatory phenotype, which is replaced with an immune inhibitory phenotype as lesions progress to cancer. Since Th17 cells are prominent at the premalignant lesion state and their levels are supported by IL-23, studies used mice that were IL-23 receptor deficient (IL-23R KO) to determine the requirement for IL-23 signaling in the immunological and clinical status of mice with premalignant oral lesions. The results showed a dependence on IL-23 signaling for the pro-inflammatory state of mice with oral lesions as levels of IL-2, IFN-γ, IL-6, IL-17 and TNF-α were elevated in wildtype mice with premalignant oral lesions, but not in IL-23R KO mice. In contrast, as lesions progressed to cancer, the pro-inflammatory phenotype subsided and was replaced with the inhibitory mediator IL-10 and with Treg cells in wildtype mice, although not in IL-23R KO mice. Clinically, early progression of premalignant oral lesions to cancer was enhanced in IL-23R KO mice compared to progression in wildtype mice. These results show the importance of IL-23 signaling in both the pro-inflammatory phenotype characteristic of premalignant oral lesions and the inhibitory phenotype as lesions progress to cancer.

Autocrine motility-stimulatory pathways of oral premalignant lesion cells.

Patients with premalignant oral lesions have varying levels of risk of developing oral squamous cell carcinoma (OSCC), whose aggressiveness requires increased motility. Not known is if and how premalignant oral lesion cells acquire the increased motility characteristic of OSCC. This was addressed by immunohistochemical analysis of banked premalignant lesion tissues and by functional analyses using cultures established from premalignant oral lesions and OSCC. These studies showed premalignant oral lesion cells and OSCC to be more motile than normal keratinocytes. Concomitantly, levels of ceramide were reduced. The activity of the protein phosphatase PP-2A, which restricts motility and which can be activated by ceramide, was also diminished. This was due to IL-10 released from premalignant lesion cells. Treatment with a membrane-permeable ceramide restored PP-2A activity and blocked migration. These studies show an autocrine motility-stimulatory pathway that is mediated in premalignant lesion cells by IL-10 through its reduction of ceramide levels and inhibition of PP-2A activity.

Redirecting the focus of cancer immunotherapy to premalignant conditions.

Much progress has been made in introducing immunological treatment approaches for cancer, with lessons learned from both the successes and failures of immunotherapy. Among the challenges of immunotherapeutic approaches for cancer are the multitudes of mechanisms by which cancers are known to subvert the immune defenses. This has led to the incorporation into the immunotherapeutic arsenal strategies by which to overcome the cancer's immunological blockades. What has been only superficially explored is the immunological milieu of premalignant lesions and the possibility of immunological approaches for the treatment of premalignant lesions so as to prevent secondary premalignant lesions and their progression to cancer. This review discusses the immunological environment associated with premalignant lesions, and the possible missed opportunity of utilizing immunological treatment strategies in the less hostile environment of premalignant lesions as compared to the immune subversive cancer environment.