Spontaneous regression of malignant melanoma - is it based on the interplay between host immune system and melanoma antigens?

Malignant melanoma (MM) is the most aggressive and uneasily treatable form of skin cancer. Up to 90% of deaths because of skin tumours are estimated to be caused by this malignancy. Spontaneous regression is described as a partial or complete disappearance of cancer. It can be defined if the clinical and histological diagnosis of malignancy is verified and any therapeutic intervention potentially inducing mechanisms leading to regression has not been applied. Regression occurs more frequently in melanoma than in other types of tumours; it is reported to be six times higher than in other malignancies. Up to 50% of primary MM is reported to undergo spontaneous regression. However, spontaneous regression of the metastatic form of tumour is a rare phenomenon observed in only 0.23% of cases. The most frequently mentioned factors leading to spontaneous regression of MM are operative trauma, infection, vaccination (BCG and rabies vaccines) and immunological factors. Other well-documented circumstances associated with regression of metastatic MM include blood transfusion and various endocrine factors.

Current concepts of immune based treatments for patients with HCC: from basic science to novel treatment approaches.

The recent approval of two immune checkpoint inhibitors for the treatment of malignant melanoma has sparked great interest by physicians and basic scientists searching for novel therapeutics for GI cancer. Chronic inflammation is recognised as a major risk factor for the development of hepatocellular carcinoma (HCC) and makes this type of cancer a potentially ideal target for an immune based treatment approach. Further evidence for a critical role of immune responses in patients with HCC is derived from the fact that immune signatures and profiles predict patients' outcome as well as the fact that tumour-induced spontaneous antitumour immunity can be detected. In addition ablative therapies can lead to changes in the number, phenotype and function of different immune cell subsets, which correlate with patients' survival. Various HCC-specific mouse models have been developed, which improve our understanding of hepatocarcinogenesis and tumour-immune cell interactions, and lead to the development of novel immune based treatment approaches, which are currently being evaluated in preclinical and in early clinical settings. Immune checkpoint blockade along with adoptive immune cell therapy and vaccine approaches are currently being evaluated either alone or in combination with other treatments. Here, we provide an overview for the rationale of immunotherapy in HCC, summarise ongoing studies and provide a perspective for immune based approaches in patients with HCC.

ATM-dependent spontaneous regression of early Eµ-myc-induced murine B-cell leukemia depends on natural killer and T cells.

Mechanisms of spontaneous tumor regression have been difficult to characterize in a systematic manner due to their rare occurrence and the lack of model systems. Here, we provide evidence that early-stage B cells in Eµ-myc mice are tumorigenic and sharply regress in the periphery between 41 and 65 days of age. Regression depended on CD4(+), CD8(+), NK1.1(+) cells and the activation of the DNA damage response, which has been shown to provide an early barrier against cancer. The DNA damage response can induce ligands that enhance immune recognition. Blockade of DNAM-1, a receptor for one such ligand, impaired tumor regression. Hence, Eµ-myc mice provide a model to study spontaneous regression and possible mechanisms of immune evasion or suppression by cancer cells.

Spontaneous Involution of Congenital Melanocytic Nevus With Halo Phenomenon.

Congenital melanocytic nevus (CMN) is a neural crest-derived hamartoma, which appear at or soon after birth. CMN has a dynamic course and may show variable changes over time, including spontaneous involution. Spontaneous involution of CMN is a rare phenomenon and is often reported in association with halo phenomenon or vitiligo. The mechanism of halo phenomenon is yet to be investigated but is suggested to be a destruction of melanocytes by immune responses of cytotoxic T cells or IgM autoantibodies. Here, the authors report an interesting case of spontaneously regressed medium-sized CMN with halo phenomenon and without vitiligo, which provides evidence that cytotoxic T cells account for the halo formation and pigmentary regression of CMN.

Assessment of regression in successive primary melanomas.

INTRODUCTION AND OBJECTIVES: It has been suggested that patients who have had a melanoma may develop increased immunity against certain antigens expressed by tumor-associated melanocytes. Thus our objective was to review the records of patients with successive primary melanomas to ascertain whether the pattern of regression might indicate the presence of an immunization effect arising from the first melanoma. MATERIAL AND METHODS: A review of all the cases recorded in the melanoma database of our dermatology department between 2000 and 2012 identified 19 patients who had multiple asynchronous melanomas (2.56% of all the cases recorded). We studied the presence or absence of regression in these melanomas and other clinical and histological characteristics. RESULTS: The presence of regression was significantly higher in successive melanomas than in the first tumors identified (42.10% vs 21.05%, P=.018). Regression of at least 1 melanoma was observed in 42.10% of the patients studied and regression of 2 melanomas was observed in 21.05%. In no case was regression observed in the first melanoma and not in the second; however, in 21.05% of the patients there was evidence of regression in the second tumor and none in the first. CONCLUSIONS: Our findings suggest the possibility that the first melanoma produces an immunization effect in some patients who develop multiple asynchronous melanomas.

Rapid spontaneous regression of acute-onset vulvar intraepithelial neoplasia 3 in young women: a case series.

OBJECTIVE: Vulvar intraepithelial neoplasia 3 (VIN 3)/vulvar carcinoma in situ is currently treated by surgical excision, laser ablation, or topically with 5-fluorouracil or imiquimod. The rate of progression of untreated VIN 3/vulvar carcinoma in situ to invasive cancer is significant, although difficult to assess, because most patients undergo treatment. The peak incidence of invasive carcinoma of the vulva occurs in the sixth decade, which may indicate that human papillomavirus (HPV)-related preinvasive disease in the younger population has a lower progression rate. However, the risk of invasive disease cannot be disregarded. METHODS: This is a case series of complete spontaneous resolution of untreated VIN 3/vulvar carcinoma in situ in 5 healthy women aged 20 to 36 years from a single community gynecologic oncologist practice from 2006 to 2010. RESULTS: Complete spontaneous regression of acute VIN 3/vulvar carcinoma in situ was reported in 6 healthy young women aged 20 to 36 years. New sexual partners were reported in 2 of the 6 patients preceding the onset of vulvar lesions within 6 months. All patients were nonsmokers, healthy without known immunocompromise, and noted the acute onset of vulvar lesions. Vulvar intraepithelial neoplasia 3/vulvar carcinoma in situ was diagnosed on biopsy and confirmed on independent review. All lesions were multifocal in nature. Time to spontaneous regression was 6, 6, 8, 12, 18, and 20 weeks after initial biopsy. No patient received the HPV vaccine. Recurrence has not been noted in any of the patients within the follow-up period of 6 to 60 months. CONCLUSIONS: Short-term follow-up with conservative management of acute-onset VIN 3/vulvar carcinoma in situ in this young patient population correlates with similar treatment strategies for HPV-related cervical intraepithelial neoplasia of the cervix and may prevent disfigurement, pain, and complications associated with the current recommended therapeutic modalities. The timing of intervention for VIN 3/vulvar carcinoma in situ in the young population needs clarification. Future studies are in order.

Pattern of MHC class I and immune proteasome expression in Walker 256 tumor during growth and regression in Brattleboro rats with the hereditary defect of arginine-vasopressin synthesis.

Dynamics of the expression of MHC class I, immune proteasomes and proteasome regulators 19S, PA28, total proteasome pool and proteasome chymotrypsin-like activity in Walker 256 tumor after implantation into Brattleboro rats with the hereditary defect of arginine-vasopressin synthesis was studied. The tumor growth and regression in Brattleboro rats were accompanied by changes in the proteasome subunit level unlike the tumor growth in WAG rats with normal expression of arginine-vasopressin gene. In the tumor implanted into Brattleboro rats the immune proteasome level was maximal between days 14 and 17, when the tumor underwent regression. Conversely, the expression of proteasome regulators tended to decrease during this period. Immune proteasomes are known to produce antigen epitopes for MHC class I to be presented to CD8+ T lymphocytes. Enhanced expression of immune proteasomes coincided with the recovery of MHC class I expression, suggesting the efficient presentation of tumor antigens in Brattleboro rats.

Naturally occurring systemic immune responses to HPV antigens do not predict regression of CIN2/3.

Essentially all squamous cervical cancers and their precursor lesions, high grade cervical intraepithelial neoplasia (CIN2/3), are caused by persistent human papillomavirus (HPV) infection. However, not all CIN2/3 lesions progress to cancer. In a brief, observational study window monitoring subjects with CIN2/3 from protocol entry (biopsy diagnosis) to definitive therapy (cervical conization) at week 15, in a cohort of 50 subjects, we found that 26% of CIN2/3 lesions associated with HPV16, the genotype most commonly associated with disease, underwent complete histologic regression. Nonetheless, HPV16-specific T cell responses measured in peripheral blood obtained at the time of study entry and at the time of conization were marginally detectable directly ex vivo, and did not correlate with lesion regression. This finding suggests that, in the setting of natural infection, immune responses which are involved in elimination of cervical dysplastic epithelium are not represented to any great extent in the systemic circulation.

Local immune response in the microenvironment of CIN2-3 with and without spontaneous regression.

Fifteen to thirty percent of cases with histologically confirmed CIN2-3 in cervical biopsies regress spontaneously (ie, show CIN1 or less in the follow-up cervical cone). The balance between immune-reactive cells from the host and high-risk human papillomavirus (hrHPV) genotypes may provide a biological explanation for this phenomenon. We retrospectively studied 55 cases of CIN2-3 in a cervical biopsy with subsequent cervical cone to assess whether hrHPV genotypes (by AMPLICOR and Linear Array tests) CD4, CD8, CD25, CD138 and Foxp3 cells (by quantitative immunohistochemistry) in the cervical biopsies can predict regression (defined as CIN1 or less in the follow-up cone biopsy). Eighteen percent of the CIN2-3 cases regressed (median biopsy-cervical cone time interval: 12.0 weeks, range: 5.0-34.1 weeks). HPV-16 correlated with low CD8+ and high CD25+. None of the regressing CIN2-3 lesions contained HPV-16. The regressing CIN2-3 lesions had lower numbers of stromal CD138+ and higher numbers of stromal CD8+cells; higher stromal and intra-epithelial ratios of CD4+/CD25+ cells; higher ratios of CD8+/CD25+ cells and lower ratios of CD8+/CD4+, CD138+/Foxp3+ and CD25+/Foxp3+ cells in the stroma. With multivariate survival analysis, stromal CD8+ cell numbers, CD4+/CD25+ cell ratios and CD138+ cell numbers are found to be independent regression predictors. In conclusion, in non-HPV-16 CIN2-3 lesions, assessing stromal immune cells can be a useful prognostic indicator of regression or persistence.

The spectrum of resistance in SR/CR mice: the critical role of chemoattraction in the cancer/leukocyte interaction.

BACKGROUND: Spontaneous regression/complete resistance (SR/CR) mice are a unique colony of mice that possess an inheritable, natural cancer resistance mediated primarily by innate cellular immunity. This resistance is effective against sarcoma 180 (S180) at exceptionally high doses and these mice remain healthy. METHODS: In this study, we challenged SR/CR mice with additional lethal transplantable mouse cancer cell lines to determine their resistance spectrum. The ability of these transplantable cancer cell lines to induce leukocyte infiltration was quantified and the percentage of different populations of responding immune cells was determined using flow cytometry. RESULTS: In comparison to wild type (WT) mice, SR/CR mice showed significantly higher resistance to all cancer cell lines tested. However, SR/CR mice were more sensitive to MethA sarcoma (MethA), B16 melanoma (B16), LL/2 lung carcinoma (LL/2) and J774 lymphoma (J774) than to sarcoma 180 (S180) and EL-4 lymphoma (EL-4). Further mechanistic studies revealed that this lower resistance to MethA and LL/2 was due to the inability of these cancer cells to attract SR/CR leukocytes, leading to tumor cell escape from resistance mechanism. This escape mechanism was overcome by co-injection with S180, which could attract SR/CR leukocytes allowing the mice to resist higher doses of MethA and LL/2. S180-induced cell-free ascites fluid (CFAF) co-injection recapitulated the results obtained with live S180 cells, suggesting that this chemoattraction by cancer cells is mediated by diffusible molecules. We also tested for the first time whether SR/CR mice were able to resist additional cancer cell lines prior to S180 exposure. We found that SR/CR mice had an innate resistance against EL-4 and J774. CONCLUSIONS: Our results suggest that the cancer resistance in SR/CR mice is based on at least two separate processes: leukocyte migration/infiltration to the site of cancer cells and recognition of common surface properties on cancer cells. The infiltration of SR/CR leukocytes was based on both the innate ability of leukocytes to respond to chemotactic signals produced by cancer cells and on whether cancer cells produced these chemotactic signals. We found that some cancer cells could escape from SR/CR resistance because they did not induce infiltration of SR/CR leukocytes. However, if infiltration of leukocytes was induced by co-injection with chemotactic factors, these same cancer cells could be effectively recognized and killed by SR/CR leukocytes.

Correlation of high and decreased NY-ESO-1 immunity to spontaneous regression and subsequent recurrence in a lung cancer patient.

We show correlation between strong and decreased NY-ESO-1-specific immunity with spontaneous regression and subsequent recurrence, respectively, in a long-surviving patient with an NY-ESO-1-expressing lung adenocarcinoma. An integrated immune response consisting of IgG antibody, as well as CD4 and CD8 T cells, against NY-ESO-1 was observed at the time of spontaneous regression of multiple pleural metastases. After tumor dormancy for 3 years, the tumor started to progress. IgG antibody levels and the number of CD4 and CD8 T cells against NY-ESO-1 decreased, but were still detectable. On the other hand, the number of Foxp3+ CD25 high T regulatory cells gradually increased. The findings suggest the relevance of the NY-ESO-1 immune response and its regulation by Foxp3+ CD25 high T regulatory cells in the clinical course of this lung cancer patient.

Spontaneous regression of primary cutaneous Epstein-Barr virus-positive, CD30-positive anaplastic large T-cell lymphoma in a heart-transplant recipient.

We presented a rare case of primary cutaneous Epstein-Barr virus-positive, CD30-positive anasplastic large cell lymphoma in a 64-year-old man who had received a heart transplant 11 years previously. The first presenting symptom was the appearance of erythematous skin nodules on the right leg. The lesions subsided with dose reduction of immunosuppressant alone. There was no recurrence 9 months after the first diagnosis. We propose that dose reduction of immunosuppressant alone may be an effective treatment for localized, indolent, post-transplant-related primary cutaneous lymphoma. Our case shows the importance of regular surveillance of skin cancer in patients who have received organ transplant.

Extracellular signal-regulated kinase activation of self-healing Langerhans cell histiocytosis: A case report.

A 3-month-old boy developed small papules on his trunk. After the papules increased in number, the patient was diagnosed with Langerhans cell histiocytosis based on the pathological findings. He was referred to our department for further examination. Upon initial examination, the papules and nodules were scattered on his back, abdomen and lumbar region. Because he did not present with any organ involvement except the skin, he was diagnosed with single-system and skin-limited Langerhans cell histiocytosis. Skin rashes were treated with a topical steroid and started regressing 3 months after onset. All papules disappeared 6 months after onset. In this boy, the Langerhans cell histiocytosis tumor cells expressed phosphorylated extracellular signal-regulated kinases. In Langerhans cell histiocytosis, BRAF V600E and other genes are known to mutate to act as driver mutations in stem cells of the myeloid dendritic cell lineage. Consequently, extracellular signal-regulated kinases are continuously activated, which contributes to Langerhans cell histiocytosis carcinogenesis.

The involvement of granulocytes in spontaneous regression of Walker 256 carcinoma.

We described before that oxidative burst of granulocytes is cytotoxic for melanoma B16F10 and for Walker 256 carcinoma (W256). Therefore, we assumed that granulocytes could also be important mechanism of the host defence against tumour. In current study we report massive granulocyte infiltration at the site of W256 transplanted in the hind limb of Sprague-Dawley associated with spontaneous tumour regression observed for 22/25 rats (87%). Peripheral blood granulocytes of these animals were highly cytotoxic for W256 cells cultured in vitro. After the tumour disappearance the inflammatory oxidative burst of the granulocytes ended. Distraction of granulocytes from the tumour by s.c. Sephadex injection decreased the incidence of the W256 regression to only 7/25 animals (30%). These results suggest that innate immunity based on immune competent granulocytes may be the cause of well known phenomenon of spontaneous regression of W256 carcinoma.

Spontaneous regression of small cell lung cancer.

Spontaneous regression of cancers is extremely rare and is associated with specific malignancies. Spontaneous regression of bronchogenic lung cancer has rarely been reported, and regression of small cell lung cancer is even less common. Such regression is generally ascribed to immunological factors but is not well understood. This case report describes a patient with spontaneous regression of small cell lung cancer that has persisted for 11 years and considers possible mechanisms.

[Spontaneous regression of lung metastases from renal cell carcinoma: the importance of immunogenetic factors and a review of the literature]. / Regressione spontanea delle metastasi polmonari da carcinoma renale. Ipotesi immunogenetiche e revisione della letteratura.

Spontaneous regression of renal cell cancer (RCC) metastases most frequently occurs after nephrectomy, since reducing target size makes possible a more effective immune response. RCC is immunotherapy-sensitive, as are RCC metastases, especially metastases to the lungs (organs are rich in immune cells and continually exposed to antigens), which have an antigenic effect. Immunotherapy could be perfected if a renal antigen that could be incorporated into a vaccine were identified. This would have played an important role in treatment and follow-up. Vaccine therapy for RCC is no longer far out of reach. The characteristics of RCC make it a fertile field for the study of prometastatic and endogenous antiangiogenic factors.

Immune phenomena involved in the in vivo regression of fibrosarcoma cells expressing cell-associated IL-1alpha.

Constitutive expression of cell-associated, but not secreted, interleukin-1alpha (IL-1alpha) by oncogene-transformed fibrosarcoma cells induced regressing tumors in mice, a phenomenon that was abrogated by the IL-1 inhibitor, the IL-1 receptor antagonist (IL-1Ra). On the contrary, non-IL-1alpha-expressing tumor cells induce progressive tumors in mice. In vivo and ex vivo experiments have shown that regression of IL-1alpha-positive fibrosarcoma cells depends on CD8(+) T cells, which can also be activated in CD4(+) T cell-depleted mice, with some contribution of natural killer cells. In spleens of mice bearing the non-IL-1alpha-expressing fibrosarcoma cells, some early and transient manifestations of antitumor-specific immunity, such as activation of specific proliferating T cells, are evident; however, no development of cytolytic T lymphocytes or other antitumor protective cells could be detected. In spleens of mice bearing the non-IL-1alpha-expressing fibrosarcoma cells, the development of early tumor-mediated suppression was observed, and in spleens of mice injected with IL-1alpha-positive fibrosarcoma cells, protective immunity developed in parallel to tumor regression. Treatment of mice bearing violent fibrosarcoma tumors with syngeneic-inactivated, IL-1alpha-positive fibrosarcoma cells, at a critical interval after injection of the malignant cells (Days 5-12), induced tumor regression, possibly by potentiating and amplifying transient antitumor cell immune responses or by ablation of tumor-mediated suppression. Membrane-associated IL-1alpha may thus serve as an adhesion molecule, which allows efficient cell-to-cell interactions between the malignant and immune effector cells that bear IL-1Rs and function as a focused cytokine with adjuvant activities at nontoxic, low levels of expression. Our results also point to the potential of using antitumor immunotherapeutic approaches using cell-associated IL-1alpha.

The microenvironment in primary cutaneous melanoma with associated spontaneous tumor regression: evaluation for T-regulatory cells and the presence of an immunosuppressive microenvironment.

Spontaneous tumor regression, regression in the absence of therapeutic intervention, can be identified histologically in over 25% of primary cutaneous melanomas at initial diagnosis. A unique subset of T lymphocytes found in areas of regression can be histologically distinguished from tumor-infiltrating T lymphocytes (TIL) found in areas of tumor progression. We call this unique subset of T lymphocytes regression-associated T lymphocytes (RATs). The aim of this study is to determine the phenotype of lymphocytes and the density of specific cell types linked to immunosuppression in areas of tumor progression compared with areas of tumor regression. These specific cell types include T-regulatory cells (Tregs) and S100A9 cells. A total of 14 primary cutaneous melanomas with areas of progression and regression were used. Immunohistochemistry staining was used to identify CD4 cells, CD8 cells, Tregs, and S100A9 cells. Two independent observers manually counted three high-powered ×40 fields. There was no predominance of CD4 or CD8 T lymphocytes in either RATs or TIL. We identified a lower density of Tregs in RATs compared with TIL when using the FOXP3/CD4 Treg marker (P=0.04) and a marginal difference when using our second, confirmatory Treg marker, FOXP3/CD25 (P=0.11). We observed a lower density of S100A9 cells in RATs compared with TIL (P=0.002). There was an observable difference in the tumor microenvironments of RATs and TIL, with RATs having a significantly lower density of Tregs and S100A9 cells. We deduce that the absence of immunosuppression in areas of regression allows for a more robust immune response and thus effective eradication of tumor cells.