Melanoma Tumor Progression Research Articles

Tanshinol inhibits growth of malignant melanoma cells via regulating miR-1207-5p/CHPF pathway.

Tanshinol possesses anti-tumor activity in melanoma both in vitro and in vivo, and miR-1207-5p is involved in tumor progression in melanoma. However, whether miR-1207-5p can be affected by tanshinol treatment in melanoma is not clear. The expression levels of miR-1207-5p were detected by RT-qPCR. The validation of the direct target of miR-1207-5p was through dual-luciferase reporter assay and western blotting assay. The cell viability rate was determined using MTT assay and colony formation assay. The cell mobility was assessed using Transwell migration/invasion assay. Downregulation of miR-1207-5p was found in melanoma cell lines and tissues and was associated with tumor stages, presence of ulceration, lymph node metastasis, and poor overall survival rate of melanoma patients. Tanshinol treatment and miR-1207-5p overexpression suppressed melanoma cell growth and cell mobility. Chondroitin polymerizing factor (CHPF) is a direct target of miR-1207-5p. Tanshinol exerted anti-tumor activity to melanoma through the regulation of miR-1207-5p/CHPF signaling. Our study highlighted the potential therapeutic application of tanshinol and miR-1207-5p as a supplement to enhance the effect of the traditional cancer treatment methods against melanoma.

Current research analysis and prospects on sensitization effect of artesunate on anti-cancer radiotherapy and chemotherapy

The wide application of artemisinins in the treatment of multiple cancers reflects the advantages of traditional Chinese medicine used in this field. The existing basic and clinical studies have revealed that artesunate can effectively suppress the malignant progression of breast cancer,colon cancer,leukemia,melanoma,ovarian cancer,prostate cancer,kidney cancer and various tumors in central nervous system. The pharmacological mechanisms of artesunate against cancers are reflected in many aspects,such as inhibiting tumor cell proliferation,invasion and metastasis,inducing tumor cell apoptosis and autophagy,regulating cell signal transduction and inhibiting tumor angiogenesis. Meanwhile,growing experimental evidences have indicated that artesunate has been used for the sensitization of radiotherapy with X-ray,β-ray,γ-ray and~(60)Co γ-ray,as well as chemotherapy with cisplatin,carboplatin and doxorubicin.This review collected basic and clinical studies on the sensitization effect of artesunate on anti-cancer radiotherapy and chemotherapy published on PubMed and CNKI during April 2000 and February 2019,and summarized the clinical positioning and application of artesunate,with the aim to provide a more comprehensive explanation on the sensitization effect of artesunate on anti-cancer radiotherapy and chemotherapy,and offer the inspiration and ideas for the development of radiotherapy and chemotherapy sensitizers,as well as cancer resistance reversal agents.

Lymphatic Control of the Tumor Immune Microenvironment

Tumor engagement or activation of surrounding lymphatic vessels is well-known to correlate with tumor progression and metastasis in melanoma and many other cancers. We and others have identified several mechanisms by which the lymphatic growth factor VEGF-C and lymphangiogenesis can promote metastasis, including (i) increasing immune suppressive cell types and factors in the tumor microenvironment both directly and indirectly, (ii) inhibiting maturation of antigen-presenting cells and T cell activation, and (iii) driving changes in the stromal microenvironment that promote both cancer invasion and immune suppression. However, lymphatic activation also enhances communication with cells in the draining lymph node by antigen and cell transport, which may trigger the initiation of adaptive immune responses against the tumor. Under normal conditions, the potential anti-tumor effects are rendered 'dormant' by the pro-tumor immune suppression, and the tumor progresses. However, we are now observing that lymphangiogenic tumors are exceptionally responsive to immunotherapy, implying that the anti-tumor aspects can be unleashed when the overall balance of pro- and anti-tumor immune aspects is tipped enough towards the latter (e.g., upon tumor cell killing). On the mechanistic side, we are finding that 'lymphangiogenic potentiation' depends on tumor cell infiltration of both CD103+ dendritic cells and naïve T cells, driving local T cell education post-immunotherapy and antigen spreading. On the translational side, we are developing novel strategies to exploit lymphangiogenesis for cancer immunotherapy. Understanding the yin and yang of lymphatic activation in the tumor microenvironment and how it affects immunity may lead to exciting new translational strategies for cancer immunotherapy. Disclosures No relevant conflicts of interest to declare.

Evidence and impact of neutrophil extracellular traps in malignant melanoma.

Ulceration of melanoma is associated with neutrophil infiltrates and lower survival rates opposite to non-ulcerated melanoma. Neutrophils release neutrophil extracellular traps (NETs) that are chromatin structures loaded with antimicrobial proteins. Since NETs have been correlated with tumor progression, we investigated whether NETs appear in melanoma and affect melanoma cells. Indeed, human primary melanoma biopsies revealed neutrophils releasing NETs in all of 27 ulcerated melanomas, whereas NETs were absent in all of 7 non-ulcerated melanomas. However, the quantity of intratumoral NETs did not correlate with tumor progression of melanoma. Interestingly, in vitro assays showed that melanoma cells attach to NETs via integrin-mediated adhesion and that NETs inhibit tumor cell migration. Moreover, co-culturing of NETs and melanoma cells had a cytotoxic effect on melanoma cells resulting in necrosis. Hence, we discovered in vitro an antineoplastic role of NETs in melanoma.

Role of angiogenesis in melanoma progression: Update on key angiogenic mechanisms and other associated components.

Angiogenesis, the formation of new blood vessels from existing blood vessels, is a complex and highly regulated process that plays a role in a wide variety of physiological and pathological processes. In malignancy, angiogenesis is essential for neoplastic cells to acquire the nutrients and oxygen critical for their continued proliferation. Angiogenesis requires a sequence of well-coordinated events mediated by a number of tightly regulated interactions between pro-angiogenic factors and their corresponding receptors expressed on various vascular components (e.g., endothelial cells and pericytes) and stromal components forming the extracellular matrix. In this review, we discuss the functional roles of key growth factors and cytokines known to promote angiogenesis in cutaneous melanoma and key factors implicated in the extracellular matrix remodeling that acts synergistically with angiogenesis to promote tumor progression in melanoma, incorporating some of the most up-to-date basic science knowledge from recently published in vivo and in vitro experimental studies.

β-Catenin Expression and Activation in Conjunctival Melanoma

Purpose: To assess the role of the canonical Wnt pathway via activation of β-catenin in tumor progression of conjunctival melanoma. Methods: β-Catenin localization was assessed by immunohistochemistry in 43 conjunctival nevi, 48 primary acquired melanoses (PAM; conjunctival melanocytic intraepithelial neoplasia), and 44 conjunctival melanomas. Activation of the canonical or the noncanonical Wnt pathway was tested in vitro in 4 conjunctival melanoma cell lines with stimulation of either Wnt5a or Wnt3a. Wound healing assays were performed with Wnt5a. Results: Nuclear β-catenin expression was found in 16% of the nevi, in 15% of the melanomas, and in 4% of the PAM. Membranous β-catenin expression was identified in all the nevi and PAM and in 97.7% of the melanomas. In vitro, Wnt5a stimulation in the 4 conjunctival melanomas and in 1 skin melanoma cell line did not induce nuclear translocation of β-catenin, nor did it increase cell motility in the wound healing assays. Wnt3a stimulation did not induce nuclear localization of β-catenin in any of the cell lines tested. Conclusions: In conjunctival melanoma, nuclear localization and activation of β-catenin appear to be limited, suggesting that inhibition of ARF6, responsible for β-catenin activation, in subsets of skin melanoma may not represent a treatment option for this tumor. In vitro, Wnt3a or Wnt5a did not induce nuclear β-catenin localization.

Melanoma Progression Inhibits Pluripotency and Differentiation of Melanoma-Derived iPSCs Produces Cells with Neural-like Mixed Dysplastic Phenotype

SummaryMelanomas are known to exhibit phenotypic plasticity. However, the role cellular plasticity plays in melanoma tumor progression and drug resistance is not fully understood. Here, we used reprogramming of melanocytes and melanoma cells to induced pluripotent stem cell (iPSCs) to investigate the relationship between cellular plasticity and melanoma progression and mitogen-activated protein kinase (MAPK) inhibitor resistance. We found that melanocyte reprogramming is prevented by the expression of oncogenic BRAF, and in melanoma cells harboring oncogenic BRAF and sensitive to MAPK inhibitors, reprogramming can be restored by inhibition of the activated oncogenic pathway. Our data also suggest that melanoma tumor progression acts as a barrier to reprogramming. Under conditions that promote melanocytic differentiation of fibroblast- and melanocyte-derived iPSCs, melanoma-derived iPSCs exhibited neural cell-like dysplasia and increased MAPK inhibitor resistance. These data suggest that iPSC-like reprogramming and drug resistance of differentiated cells can serve as a model to understand melanoma cell plasticity-dependent mechanisms in recurrence of aggressive drug-resistant melanoma.

A small-molecule antagonist of CXCR1 and CXCR2 inhibits cell proliferation, migration and invasion in melanoma via PI3K/AKT pathway

IntroductionMelanoma is the most dangerous skin cancer with high metastasis rate and mortality. Although the emergence of immunotherapy has brought hope for treatment, the mortality rate of melanoma is still increasing year by year. The underlying mechanism of melanoma tumor progression and metastasis is urgently needed to be clarified. Recently chemokines have been found to play an important role in tumor progression in addition to their immunocytochemical chemotaxis. MethodsIn this study, human melanoma cell lines A375 and M14 were treated with SCH-527123, a small molecule antagonist of CXCR1 and CXCR2. The effects of treatment with SCH-527123 on melanoma cell proliferation, migration and invasion were evaluated in vitro by CCK-8, colony formation and transwell assays. Apoptosis was also detected by flow cytometry staining with annexin V and propidium iodide (PI). The molecular mechanisms of antagonist mediated were detected by western blot. ResultsThe results showed that SCH-527123 inhibited the proliferation, migration and invasion of melanoma cell lines and promoted apoptosis. The expression of CXCR1 and CXCR2 was downregulated after treatment with SCH-527123. PI3K/AKT pathway and downstream signaling were also inhibited at molecular level owing to treated with SCH-527123. ConclusionIn conclusion, our study demonstrated that SCH-527123, a small-molecule antagonist for CXCR1 and CXCR2 inhibited cell proliferation, migration and invasion in melanoma via PI3K/AKT pathway.

Myeloid-Derived Suppressor Cells: Not Only in Tumor Immunity.

Since the realization that immature myeloid cells are powerful modulators of the immune response, many studies on “myeloid-derived suppressor cells” (MDSCs) have documented their ability to promote tumor progression in melanoma and other cancers. Whether MDSCs are induced solely pathologically in tumorigenesis, or whether they also represent physiological immune control mechanisms, is not well-understood, but is particularly important in the light of ongoing attempts to block their activities in order to enhance anti-tumor immunity. Here, we briefly review studies which explore (1) how best to identify MDSCs in the context of cancer and how this compares to other conditions in humans; (2) what the suppressive mechanisms of MDSCs are and how to target them pharmacologically; (3) whether levels of MDSCs with various phenotypes are informative for clinical outcome not only in cancer but also other diseases, and (4) whether MDSCs are only found under pathological conditions or whether they also represent a physiological regulatory mechanism for the feedback control of immunity. Studies unequivocally document that MDSCs strongly influence cancer outcomes, but are less informative regarding their relevance to infection, autoimmunity, transplantation and aging, especially in humans. So far, the results of clinical interventions to reverse their negative effects in cancer have been disappointing; thus, developing differential approaches to modulate MSDCs in cancer and other diseases without unduly comprising any normal physiological function requires further exploration.

Immunoexpression of SPANX-C in metastatic uveal melanoma

Uveal melanoma is a rare disease but it is the most common primary intraocular malignant tumor in adults with poor late prognosis. About 50% of patients will develop liver metastasis far from the enucleation within 10–15 years. Our study examined SPANX-C expression levels in primary uveal melanoma both with and without metastasis to assess if they can be used to predict metastasis. This study included a total of 55 patients, 28 males and 27 females, with uveal melanoma. A significantly high expression of SPANX-C was seen in 19/23 (82.6%) patients with metastasis, and only in 11/32 (38.5%) patients without metastasis. In conclusion, we found that SPANX-C expression could play a role in tumor progression of uveal melanoma.

Size Matters: The Functional Role of the CEACAM1 Isoform Signature and Its Impact for NK Cell-Mediated Killing in Melanoma.

Malignant melanoma is the most aggressive and treatment resistant type of skin cancer. It is characterized by continuously rising incidence and high mortality rate due to its high metastatic potential. Various types of cell adhesion molecules have been implicated in tumor progression in melanoma. One of these, the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), is a multi-functional receptor protein potentially expressed in epithelia, endothelia, and leukocytes. CEACAM1 often appears in four isoforms differing in the length of their extracellular and intracellular domains. Both the CEACAM1 expression in general, and the ratio of the expressed CEACAM1 splice variants appear very dynamic. They depend on both the cell activation stage and the cell growth phase. Interestingly, normal melanocytes are negative for CEACAM1, while melanomas often show high expression. As a cell–cell communication molecule, CEACAM1 mediates the direct interaction between tumor and immune cells. In the tumor cell this interaction leads to functional inhibitions, and indirectly to decreased cancer cell immunogenicity by down-regulation of ligands of the NKG2D receptor. On natural killer (NK) cells it inhibits NKG2D-mediated cytolysis and signaling. This review focuses on novel mechanistic insights into CEACAM1 isoforms for NK cell-mediated immune escape mechanisms in melanoma, and their clinical relevance in patients suffering from malignant melanoma.

UNBS5162 and amonafide inhibits tumor progression in human melanoma by the AKT/mTOR pathway.

BackgroundHuman melanoma is a malignant tumor originated from melanocytes with high invasion, metastasis, and poor prognosis. In this study, the effects of naphthalimides UNBS5162 and amonafide on the properties of proliferation and apoptosis in human melanoma cells were confirmed.MethodsCell proliferation was determined by CCK8 and clone formation assay. Transwell assay was performed to detect the migration and invasion of M14 and A375 cells. Cell apoptosis was estimated using flow cytometry.ResultsIn a drug sensitivity assay, cell viability decreased with increasing concentrations of UNBS5162 or amonafide. Likewise, proliferation of M14 or A375 cells treated with 10 μM UNBS5162 or 8 μM amonafide decreased significantly when compared with negative control (NC) cells, their inhibition effect verified by means of a clone formation assay. After the treatment with UNBS5162 or amonafide, the migration of melanoma cells was inhibited in a dosede-pendent manner. The number of invaded cells treated with UNBS5162 was also significantly reduced when compared with those of the NC cells. The apoptotic cell numbers treated with UNBS5162 or amonafide decreased significantly when compared with the M14 and A375 cells in the NC group. According to Western blot results, phosphorylation of AKT and expressions of mesenchymal marker factors were inhibited in cells treated with UNBS5162 or amonafide.ConclusionThese results reveal that UNBS5162 inhibits the cell activity of melanoma cells through the AKT/mTOR signaling pathway, and reverses epithelial–mesenchymal transition conversion in human melanoma cells. This study on UNBS5162 and amonafide in melanomas provides an experimental basis of their uses and potential value on human melanoma treatment.

Elevated nuclear auto-antigenic sperm protein promotes melanoma progression by inducing cell proliferation.

BackgroundNuclear auto-antigenic sperm protein (NASP) has been implicated in tumorigenesis. However, its role in melanoma is still unclear.Materials and methodsIn the present study, we detected the mRNA and protein level of NASP in melanoma cell lines and tissues. Then the role of NASP was investigated by transfecting with NASP siRNAs. Finally, the prognosis of NASP was analyzed in 100 melanoma patients through Cox regression and Kaplan–Meier analyses.ResultsWe showed that NASP was significantly overexpressed in melanoma tissues, and unregulated NASP promoted melanoma cell proliferation via promoting cell cycle G1/S phase transition. Additionally, the expression of NASP was closely related to proliferating cell nuclear antigen, a widely accepted biomarker for cell proliferation. Clinically, we found that a high level of NASP predicated poor overall survival and high cumulative recurrence rates. Multivariate analysis revealed that NASP was a risk biomarker for predicting the prognosis of melanoma patients.ConclusionElevated NASP plays an important role in melanoma cell proliferation and tumor progression, and it can be used as an independent prognostic biomarker for melanoma patients.

Exploring Differential Connexin Expression across Melanocytic Tumor Progression Involving the Tumor Microenvironment.

The incidence of malignant melanoma, one of the deadliest cancers, continues to increase. Here we tested connexin (Cx) expression in primary melanocytes, melanoma cell lines and in a common nevus, dysplastic nevus, and thin, thick, and metastatic melanoma tumor progression series involving the tumor microenvironment by utilizing in silico analysis, qRT-PCR, immunocyto-/histochemistry and dye transfer tests. Primary melanocytes expressed GJA1/Cx43, GJA3/Cx46 and low levels of GJB2/Cx26 and GJC3/Cx30.2 transcripts. In silico data revealed downregulation of GJA1/Cx43 and GJB2/Cx26 mRNA, in addition to upregulated GJB1/Cx32, during melanoma progression. In three melanoma cell lines, we also showed the loss of GJA1/Cx43 and the differential expression of GJB1/Cx32, GJB2/Cx26, GJA3/Cx46 and GJC3/Cx30.2. The dominantly paranuclear localization of connexin proteins explained the ~10–90 times less melanoma cell coupling compared to melanocytes. In melanocytic tumor tissues, we confirmed the loss of Cx43 protein, fall of cell membrane and elevated paranuclear Cx32 with moderately increased cytoplasmic Cx26 and paranuclear Cx30.2 positivity during tumor progression. Furthermore, we found Cx43, Cx26 and Cx30 proteins upregulated in the melanoma adjacent epidermis, and Cx43 in the tumor flanking vessels. Therefore, differential connexin expression is involved in melanocytic tumor progression where varying connexin isotypes and levels reflect tumor heterogeneity-related bidirectional adaptive interactions with the microenvironment.

Oxalomalate reduces tumor progression in melanoma via ROS-dependent proapoptotic and antiangiogenic effects

The potent cytotoxicity of reactive oxygen species (ROS) can cause various diseases, however, it may also serve as a powerful chemotherapeutic strategy capable of killing cancer cells. Oxalomalate (OMA, α-hydroxy-β-oxalosuccinic acid), a tricarboxylic acid intermediate, is a well-known competitive inhibitor of two classes of NADP+-dependent isocitrate dehydrogenase (IDH) isoenzymes, which serve as the major antioxidants and redox regulators in the mitochondria and cytosol. In this study, we investigated the therapeutic effects of OMA in melanoma and elucidated the associated underlying mechanisms of action using in vitro and in vivo models. OMA targeting IDH enzymes suppressed melanoma growth through activation of apoptosis and inhibition of angiogenesis. Mechanistically, our findings showed that OMA activated p53-mediated apoptosis through ROS-dependent ATM-Chk2 signaling and reduced the expression of vascular endothelial growth factor through ROS-dependent E2F1-mediated hypoxia inducible factor-1α degradation. In particular, OMA-induced suppression of IDH activity resulted in induction of ROS stress response, ultimately leading to apoptotic cell death and antiangiogenic effects in melanoma cells. Thus, OMA might be a potential candidate drug for melanoma skin cancer therapy.

An update on the I blood group system

This update of the I blood group system (Cooling L. Polylactosamines, there's more than meets the "Ii": a review of the I system. Immunohematology 2010;26:133-55) continues to show the Ii antigens to be increasingly recognized as important posttranslational modifiers regulating cell adhesion, signaling, differentiation, and cancer. Ii antigens can modulate the immune response through the galectin lattice, as well as influence specific protein-protein interactions. Changes in GCNT2 and I expression accompany stem cell differentiation and are associated with tumor progression in melanoma and breast and colon cancer. Regulation of GCNT2 expression varies between cell types and differentiation. In red blood cell differentiation, GCNT2 is regulated by methylation, microRNAs, and mitogen-activated protein kinase signaling pathways. Methylation and microRNAs also play a prominent role in altering GCNT2 expression in several epithelial cancers. In congenital cataracts, GCNT2 mutations may account for 4-6 percent of all cases. GCNT2 may be particularly susceptible to gene deletion and rearrangements due to the density of Alu-repeat elements.

The number and localization of CD68+ and CD163+ macrophages in different stages of cutaneous melanoma.

The role of tumor-associated macrophages (TAMs) in cutaneous melanoma is controversial. TAMs include immunogenic and immunosuppressive subtypes, and have distinct functions according to their microanatomical localization. Our aim was to investigate TAMs in benign, premalignant, and malignant melanocytic lesions to determine possible associations with tumor progression and clinicopathological characteristics. In total, 184 tissue samples, including benign and dysplastic nevi, in-situ melanomas, superficial (Breslow's depth <1 mm), and deep (Breslow's depth >4 mm) invasive melanomas and lymph node metastases, were analyzed for macrophage content. Samples were stained immunohistochemically for CD68 and CD163, representing all TAMs and M2-macrophages, respectively. Macrophages were counted by hotspot analysis, and assessed semiquantitatively from the tumor cell nests and stromal component of malignant cases. CD68+ and CD163+ TAMs were more abundant in invasive melanomas compared with benign nevi. The proportion of TAMs in the tumor nests was higher in deep melanomas and lymph node metastases compared with superficially invasive melanomas. High amounts of CD68+ macrophages in tumor cell nests were associated with recurrence, whereas low CD163+ macrophage proportion in tumor stroma was associated with recurrence and in primary melanomas also with poor overall survival. TAMs seem to promote tumor progression in cutaneous melanoma. In particular, CD68+ TAMs and their abundance in tumor nests were associated with poor prognostic factors. However, the correlation of low stromal CD163+ TAM proportion with a poor prognosis indicates that the role of TAMs depends on their subtype and microanatomical localization.

A small-molecule antagonist of CXCR1 and CXCR2 inhibits cell proliferation, migration and invasion in melanoma via PI3K/AKT pathway

IntroductionMelanoma is the most dangerous skin cancer with high metastasis rate and mortality. Although the emergence of immunotherapy has brought hope for treatment, the mortality rate of melanoma is still increasing year by year. The underlying mechanism of melanoma tumor progression and metastasis is urgently needed to be clarified. Recently chemokines have been found to play an important role in tumor progression in addition to their immunocytochemical chemotaxis. MethodsIn this study, human melanoma cell lines A375 and M14 were treated with SCH-527123, a small molecule antagonist of CXCR1 and CXCR2. The effects of treatment with SCH-527123 on melanoma cell proliferation, migration and invasion were evaluated in vitro by CCK-8, colony formation and transwell assays. Apoptosis was also detected by flow cytometry staining with annexin V and propidium iodide (PI). The molecular mechanisms of antagonist mediated were detected by western blot. ResultsThe results showed that SCH-527123 inhibited the proliferation, migration and invasion of melanoma cell lines and promoted apoptosis. The expression of CXCR1 and CXCR2 was downregulated after treatment with SCH-527123. PI3K/AKT pathway and downstream signaling were also inhibited at molecular level owing to treated with SCH-527123. ConclusionIn conclusion, our study demonstrated that SCH-527123, a small-molecule antagonist for CXCR1 and CXCR2 inhibited cell proliferation, migration and invasion in melanoma via PI3K/AKT pathway.

MiR-25 Promotes Melanoma Progression by regulating RNA binding motif protein 47.

Melanoma is the most aggressive skin cancer, and accounts for the major part of skin cancer-related deaths in the world. In addition, the underlying mechanism of tumor progression in melanoma remains far from being elucidated. In this study, we have evaluated the function of miR-25 in melanoma. First, we examined the expression of miR-25 in four melanoma cell lines (A875, MV3, M14 and uacc-257) and in a normal melanocyte cell line (HEM-a). Then, we overexpressed miR-25 in M14 cells. Our results show that miR-25 promotes M14 cell proliferation and migration. We found that miR-25 up-regulates the PI3K/Akt/mTOR signaling pathway in these tumor cells. Furthermore, a luciferase-based reporter gene assay showed that miR-25 could directly target the RNA-binding motif protein 47 (RBM47). Taken together, our findings suggest that RBM47 is a promising target for the treatment of melanoma.

Role of simvastatin in tumor lymphangiogenesis and lymph node metastasis.

Lymphangiogenesis plays a crucial role in promoting cancer metastasis to sentinel lymph nodes (LNs) and beyond. Increasing data have shown that simvastatin, a cholesterol-lowering medication for the prevention of cardiovascular diseases, is involved in tumor growth and dissemination, and endothelial functions. This study aimed to investigate the potential effect of simvastatin on lymphatic formation and LN metastasis. Tumor models were established by subcutaneous injection of B16-F10 melanoma cells into mouse hind footpads. Simvastatin was administered (0.2µg/g, intraperitoneal injection, IP) every other day for a total of eight times. Tissue samples were removed and examined by immunohistochemical staining and reverse transcription-polymerase chain reaction (RT-PCR) techniques. The lymphatics of LN, skin, liver, and lung exhibited morphological changes, and LN weight and metastatic area of the tumor group treated with simvastatin was lower than that of the untreated tumor group. Analysis of lymphatic size, area fraction, and lymphatic vessel density showed tissue specificity and variation to melanoma carcinogenesis in the simvastatin-treated group compared with the untreated group. In addition, LNs and cutaneous tissues showed altered expression of lymphangiogenic factors and inflammatory cytokines such as VEGF-A/-C/-D and TNF-α. These findings indicated that simvastatin may modify lymphangiogenesis and tumor progression in malignant melanoma.