Peritumoral SPARC expression induced by exosomes from nasopharyngeal carcinoma infected Epstein-Barr virus: A poor prognostic marker.

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) cells have high metastatic potential. Recent research has revealed that the interaction of between tumor cells and the surrounding stroma plays an important role in tumor invasion and metastasis. In this study, we showed the prognostic value of expression of SPARC, an extracellular matrix protein with multiple cellular functions, in normal adjacent tissues (NAT) surrounding NPC. In the immunohistochemical analysis of 51 NPC biopsy specimens, SPARC expression levels were significantly elevated in the NAT of EBER (EBV-encoded small RNA)-positive NPC compared to that in the NAT of EBER-negative NPC. Moreover, increased SPARC expression in NAT was associated with a worsening of overall survival. The enrichment analysis of RNA-seq of publicly available NPC and NAT surrounding NPC data showed that high SPARC expression in NPC was associated with epithelial mesenchymal transition promotion, and there was a dynamic change in the gene expression profile associated with interference of cellular proliferation in NAT, including SPARC expression. Furthermore, EBV-positive NPC cells induce SPARC expression in normal nasopharyngeal cells via exosomes. Induction of SPARC in cancer-surrounding NAT cells reduced intercellular adhesion in normal nasopharyngeal structures and promoted cell competition between cancer cells and normal epithelial cells. These results suggest that epithelial cells loosen their own binding with the extracellular matrix as well as stromal cells, facilitating the invasion of tumor cells into the adjacent stroma by activating cell competition. Our findings reveal a new mechanism by which EBV creates a pro-metastatic microenvironment by upregulating SPARC expression in NPC.

Immune-Related Gene Expression Profile at Peritumoral Tonsillar Tissue Is Modified by Oropharyngeal Cancer Nodal Status.

Secondary lymphoid organs, such as lymph nodes and tonsils, serve as an interface between the immune system and tumor cells as an initial antigen-presentation site, crucial in antitumor immune response and disease progression. In oropharyngeal cancers originating from palatine tonsils, it was hypothesized that characterizing the immunologic process occurring in the peritumoral tonsil tissue would elucidate immune mechanisms of the lymphatic spread of the disease. A total of 33 patients were enrolled and divided into two cohorts. In Cohort 1 (6 patients), gene expression profiles at the peritumoral lymph regions and tumor regions were analyzed using the whole-transcriptome atlas. In the peritumoral lymph regions, 237 genes were up-regulated in metastasis-negative cases compared with metastasis-positive ones, but only 1 gene was up-regulated in tumor regions. In Cohort 2 (27 patients), microarray analysis of peritumoral tonsil tissue revealed 192 up-regulated genes. Gene ontology analysis revealed the significantly enriched Gene Ontology terms associated with T-cell activation; top 10 hub genes, as ranked by degree, were PTPRC, TLR4, CD80, CD40, STAT3, CD28, CD40LG, CD44, CCR7, and IL7R. Gene set enrichment analysis combined with principal component analysis were used to effectively classify patients as lymph node metastasis positive or negative. These findings suggest peritumoral tonsils as a potential target for investigating the immune mechanisms associated with the lymphatic spread of the disease in oropharyngeal cancers.

EBV genome variations enhance clinicopathological features of nasopharyngeal carcinoma in a non-endemic region.

Nasopharyngeal carcinoma (NPC) is caused by infection with Epstein-Barr virus (EBV) and endemic in certain geographic regions. EBV lytic gene, BALF2, closely associates with viral reactivation and BALF2 gene variation, the H-H-H strain, causes NPC in endemic region, southern China. Here, we investigate whether such EBV variations also affect NPC in a non-endemic region, Japan. Viral genome sequencing with 47 EBV isolates of Japanese NPC were performed and compared with those of other EBV-associated diseases from Japan or NPC in Southern China. EBV genomes of Japanese NPC are different from those of other diseases in Japan or endemic NPC; Japanese NPC was not affected by the endemic strain (the BALF2 H-H-H) but frequently carried the type 2 EBV or the strain with intermediate risk of endemic NPC (the BALF2 H-H-L). Seven single nucleotide variations were specifically associated with Japanese NPC, of which six were present in both type 1 and 2 EBV genomes, suggesting the contribution of the type 2 EBV-derived haplotype. This observation was supported by a higher viral titer and stronger viral reactivation in NPC with either type 2 or H-H-L strains. Our results highlight the importance of viral strains and viral reactivation in the pathogenesis of non-endemic NPC.

Estrogen induces the expression of EBV lytic protein ZEBRA, a marker of poor prognosis in nasopharyngeal carcinoma.

Several epidemiological studies have suggested that Epstein-Barr virus (EBV) lytic infection is essential for the development of nasopharyngeal carcinoma (NPC), as the elevation of antibody titers against EBV lytic proteins is a common feature of NPC. Although ZEBRA protein is a key trigger for the initiation of lytic infection, whether its expression affects the prognosis and pathogenesis of NPC remains unclear. In this study, 64 NPC biopsy specimens were analyzed using immunohistochemistry. We found that ZEBRA was significantly associated with a worsening of progression-free survival in NPC (adjusted hazard ratio, 3.58; 95% confidence interval, 1.08-11.87; p = 0.037). Moreover, ZEBRA expression positively correlated with key endocrinological proteins, estrogen receptor α, and aromatase. The transcriptional level of ZEBRA is activated by estrogen in an estrogen receptor α-dependent manner, resulting in an increase in structural gene expression levels and extracellular virus DNA copy number in NPC cell lines, reminiscent of lytic infection. Interestingly, it did not suppress cellular proliferation or increase apoptosis, in contrast with cells treated with 12-O-tetradecanoylphorbol-13-acetate and sodium butyrate, indicating that viral production induced by estrogen is not a cell lytic phenomenon. Our results suggest that intratumoral estrogen overproduced by aromatase could induce ZEBRA expression and EBV reactivation, contributing to the progression of NPC.

Expression of estrogen receptor alpha is associated with pathogenesis and prognosis of human papillomavirus-positive oropharyngeal cancer.

Human papillomavirus (HPV) has been identified as a causative agent of cervical cancer and oropharyngeal cancer (OPC). Intriguingly, estrogen and HPV were shown to play synergistic roles in cervical carcinogenesis. We recently demonstrated that the apolipoprotein B mRNA-editing catalytic polypeptide 3 (APOBEC3, A3) family, which is inducible by estrogen, could lead to HPV DNA hypermutation and cause viral DNA integration. In the present study, we examined the relationships between estrogen-estrogen receptor α (ERα) and A3s in HPV-positive OPC. ERα expression was associated with HPV positivity in OPC biopsy samples using immunohistochemical analysis and reverse-transcription quantitative polymerase chain reaction. In addition, ERα was significantly associated with improved overall survival in HPV-positive OPC (hazard ratio, 0.26; p = 0.029). APOBEC3A (A3A) mRNA was induced by estrogen in HPV and ERα-positive OPC cells. Furthermore, A3A mRNA and protein expression were significantly higher in ERα-positive cases than in ERα-negative ones, among HPV-positive biopsy samples (p = 0.037 and 0.047). These findings suggest that A3A is associated with a good prognosis in ERα-positive OPC, and indicate the prognostic significance of ERα in HPV-positive OPC. This is the first study to demonstrate the prognostic role of ERα in HPV-positive OPC.

Bone invasion-targeted chemotherapy with a novel anionic platinum complex (3Pt) for oral squamous cell carcinoma.

Cisplatin (CDDP) is an important drug for chemotherapy in patients with head and neck squamous cell carcinoma. Nephrotoxicity and lack of an effect on bone invasion are limitations of CDDP. To increase its antitumor effect on bone invasion and reduce toxicity problems, anionic Pt complex (3Pt) has been developed. The present study aimed to characterize the basis of the cytotoxicity of the novel platinum complex 3Pt in comparison with that of CDDP for oral squamous cell carcinoma. The ionic platinum complex was prepared to increase solubility and avoid platinum nephrotoxicity. Furthermore, 3Pt was designed to target bone hydroxyapatite and has germinal bisphosphonate moieties for drug delivery. In vitro antitumor activity was assayed in two oral squamous cell carcinoma cell lines. To investigate the antitumor and nephrotoxic effects of 3Pt, nude mice with OSC-19 were given 3Pt and CDDP. The in vitro growth-inhibitory effect of 3Pt was significantly less than that of CDDP. However, both 3Pt and CDDP showed equivalent antitumor effects in vivo. Mice injected with CDDP developed renal cell apoptosis; however, those injected with 3Pt were almost free of renal cell injury. In addition to similar in vivo antitumor effects, 3Pt decreased the volume of bone resorption compared to that with CDDP in a bone invasion model using OSC-19. In conclusion, considering the potential advantages in terms of noticeable antitumor activity on bone invasion and reduced nephrotoxicity, 3Pt represents a significant improvement in the development of bone-targeting platinum drugs.

Progression of understanding for the role of Epstein-Barr virus and management of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is very common in southern China and Southeast Asia. In regions where NPC is endemic, undifferentiated subtypes constitute most cases and are invariably associated with Epstein-Barr virus (EBV) infection, whereas the differentiated subtype is more common in other parts of the world. Undifferentiated NPC is a unique malignancy with regard to its epidemiology, etiology, and clinical presentation. Clinically, NPC is highly invasive and metastatic, but sensitive to both chemotherapy and radiotherapy (RT). Overall prognosis has dramatically improved over the past three decades because of advances in management, including the improvement of RT technology, the broader application of chemotherapy, and more accurate disease staging. Despite the excellent local control with modern RT, distant failure remains a challenging problem. Advances in molecular technology have helped to elucidate the molecular pathogenesis of NPC. This article reviews the contribution of EBV gene products to NPC pathogenesis and the current management of NPC.

Modulation of the tumor microenvironment by Epstein-Barr virus latent membrane protein 1 in nasopharyngeal carcinoma.

Latent membrane protein 1 (LMP1) is a primary oncogene encoded by the Epstein-Barr virus, and various portions of LMP1 are detected in nasopharyngeal carcinoma (NPC) tumor cells. LMP1 has been extensively studied since the discovery of its transforming property in 1985. LMP1 promotes cancer cell growth during NPC development and facilitates the interaction of cancer cells with surrounding stromal cells for invasion, angiogenesis, and immune modulation. LMP1 is detected in 100% of pre-invasive NPC tumors and in approximately 50% of advanced NPC tumors. Moreover, a small population of LMP1-expressing cells in advanced NPC tumor tissue is proposed to orchestrate NPC tumor tissue maintenance and development through cancer stem cells and progenitor cells. Recent studies suggest that LMP1 activity shifts according to tumor development stage, but it still has a pivotal role during all stages of NPC development.

EBV infection is prevalent in the adenoid and palatine tonsils in adults.

Epstein-Barr virus (EBV) is associated with the pathogenesis of several diseases in both adults and children. However, there have been no reports on the prevalence and amount of EBV in the adenoids of adults; thus, it is important to investigate these in the adenoids and tonsils of adults and children. In this study, 67 patients who underwent tonsillectomy or adenotonsillectomy were included and divided into two groups: adults aged ≥ 16 years (n = 35) and children aged <16 years (n = 32). Patients' adenoid and tonsil tissues were analyzed using quantitative polymerase chain reaction for EBV DNA. EBV was detected in 26 (74%) adenoids and 25 (71%) tonsils among the adult group and was detected 21 (66%) adenoids and 20 (63%) tonsils in the child group. There was no significant difference in EBV DNA prevalence between the adenoids and tonsils for each group. However, there was a significant correlation between EBV DNA load in the adenoids and tonsils of the same individual in both groups (r = 0.579, P < 0.01, adult group; r = 0.919, P < 0.01, child group). In conclusion, EBV infection is prevalent in the adenoids and tonsils in adults and children. These results indicate that EBV continuously reside in the nasopharyngeal region after primal infection and may develop several diseases.

Expression of interferon regulatory factor 7 correlates with the expression of Epstein-Barr Virus latent membrane protein 1 and cervical lymph node metastasis in nasopharyngeal cancer.

Interferon regulatory factor 7 (IRF7) has oncogenic properties in several malignancies such as Epstein-Barr virus (EBV)-associated lymphoma. However, there is no evidence whether IRF7 is associated with the oncogenesis of nasopharyngeal cancer (NPC), the pathogenesis of which is closely associated with EBV. Herein, we report that expression of IRF7 was increased in normal nasopharyngeal cells that expressed the EBV principal oncoprotein, latent membrane protein 1 (LMP1). In addition, IRF7 was mainly expressed in the nucleus in both normal nasopharyngeal cells and nasopharyngeal cancer cells that expresses LMP1. On immunohistochemical analysis, IRF7 was predominantly localized in the nucleus in biopsy samples of NPC tissues. In total, IRF7 expression was detected with 36 of 49 specimens of these tissues. Furthermore, the expression score of IRF7 correlated with the expression score of LMP1. Moreover, the expression score of IRF7 is associated with cervical lymph-node metastasis, which reflects the highly metastatic nature of this cancer. Taken together, our results suggest that expression of IRF7 is one of the metastatic effectors of LMP1 signalling in EBV-associated NPC.

[Pharyngoesophageal Reconstruction Using a Laryngotracheal Flap Following Resection for Hypopharyngeal Cancer].

We used hemilaryngotracheal tissue without tumor involvement as a laryngotracheal flap (LTF) for immediate repair of a pharyngoesophageal defect following resection for hypopharyngeal cancer. Five cases of lateralized advanced hypopharyngeal cancer were treated in our department. The median age was 82 years, ranging from 64 to 90 years. Four tumors were T3 stage, and the other was T2. A pharyngocutaneous fistula developed in one patient. The postoperative swallowing function was satisfactory, but one patient developed difficulty in eating a normal diet, because of pharyngoesophageal stenosis at 7 months after chemoradiotherapy. During the follow-up period, there was no locoregional recurrence. One patient had lung metastasis, and died of the disease. One patient died of another cause. Three patients are alive without evidence of the disease. Reconstruction of the hypopharynx with an LTF is a minimally invasive method compared with the radial forearm free flap and free jejunal flap. For selected cases of advanced hypopharyngeal cancer, this method would be one of the choices to reconstruct the pharyngoesophageal defect.

Induction of epithelial-mesenchymal transition and loss of podoplanin expression are associated with progression of lymph node metastases in human papillomavirus-related oropharyngeal carcinoma.

AIMS: To examine human papillomavirus (HPV) status, the expression of podoplanin and epithelial-mesenchymal transition (EMT) markers and lymphatic vessel counts (LVC) in oropharyngeal squamous cell carcinoma (OPSCC) tissues, and to evaluate whether these factors were associated with survival and nodal status. METHODS AND RESULTS: A total of 53 OPSCC specimens were evaluated for HPV status and expression of proteins such as podoplanin and EMT markers by immunohistochemistry. E-cadherin-negative and vimentin-positive specimens were defined as EMT-positive. Twenty-two OPSCCs were HPV-positive. There was significant progression of nodal status in patients with HPV-positive tumours (P = 0.0475). HPV-positive cases had significantly lower expression of podoplanin (P = 0.0016) and were more frequently EMT-positive (P = 0.0172). Podoplanin-negative cases and EMT-positive cases showed significantly more advanced nodal status than their respective counterparts (P = 0.0082 and P = 0.0186, respectively). LVC correlated with neither HPV nor nodal status. Multivariate analyses revealed that HPV infection was an independent marker of longer disease-specific survival (P = 0.014). CONCLUSIONS: HPV-positivity in OPSCC was associated with loss of podoplanin expression and with EMT induction, which resulted in progression of nodal status. The mechanisms leading to an improved prognosis in HPV-positive OPSCC patients requires elucidation, as this is inconsistent with the aggressive phenotype with lymph node metastases.

Progress and controversy for the role of chemotherapy in nasopharyngeal carcinoma.

Since the publication of Intergroup Study 0099, representing a superiority of concurrent chemoradiotherapy with cisplatin followed by adjuvant chemotherapy to radiotherapy alone for the treatment of locoregionally advanced nasopharyngeal carcinoma, an efficacy of concurrent setting of cisplatin-based chemotherapy with radiotherapy has been repeatedly validated. In meanwhile, the role of adjuvant part of the protocol has been controversial. There is an increasing evidence for the positive role of neoadjuvant chemotherapy with following concurrent chemoradiotherapy whereas favorable contribution was not proven in the last century. This article reviews the role of chemotherapy in the treatment of locoregionally advanced nasopharyngeal carcinoma.

Factors associated with gastrostomy tube dependence after concurrent chemoradiotherapy for hypopharyngeal cancer.

PURPOSE: We aimed to identify tumor- and treatment-related factors predicting gastrostomy tube dependence after concurrent chemoradiotherapy (CCRT) for hypopharyngeal cancer. METHODS: We performed a retrospective review of all patients with hypopharyngeal cancer treated with CCRT between 2002 and 2012 except for those with residual or recurrent disease at evaluation. The incidence of gastrostomy tube dependence, defined as complete or almost complete dependence on tube feeding, at 6 months after the completion of treatment was the endpoint. A total of 75 patients were analyzed in this study. RESULTS: Twelve patients (16 %) showed gastrostomy tube dependence. Among tumor-related factors, the subsite (posterior wall versus pyriform sinus plus postcricoid) was the most significant factor correlated with gastrostomy tube dependence (p < 0.01 by multivariate analysis). The T category of the primary tumor was also correlated with gastrostomy tube dependence on univariate analysis (p < 0.01). Among treatment-related factors, the radiation dose was not associated with gastrostomy tube dependence. On the other hand, gastrostomy tube dependence was also correlated with the requirement of supportive nutrition with a nasogastric tube at the beginning of and during treatment (both p < 0.01). CONCLUSION: Risk factors for gastrostomy tube dependence after the completion of CCRT for hypopharyngeal cancer were identified.

HPV Status Determines the Efficacy of Adjuvant Chemotherapy With S-1, an Oral Fluorouracil Prodrug, in Oropharyngeal Cancer.

OBJECTIVES: A subgroup of oropharyngeal squamous cell carcinoma (OPC) is infected with high-risk human papillomavirus (HPV). The object of this study is to evaluate the efficacy of adjuvant chemotherapy with S-1, an oral 5-fluorouracil prodrug, on survival of patients with OPC according to HPV status. METHODS: Among OPC patients of stage III or IV who received definitive treatment from 1998 to 2008, 38 who were confirmed tumor-free after primary treatment were analyzed. Before 2003, none of the patients received S-1 adjuvant chemotherapy (S-1(-)-group); however, all patients who were eligible were administered S-1 (S-1(+)-group) after 2003. The expression of thymidylate synthase (TYMS) involved in 5-FU metabolism was also examined in protein and mRNA levels. RESULTS: Although there was a trend to disease-free and overall survival benefit in HPV-negative patients with S-1, it did not achieve statistical significance (P=.082 and P=.065, respectively). For the HPV-positive patients, the survivals were similar with or without S-1 administration. TYMS-expression in HPV-positive OPC tissues was significantly higher than in HPV-negative ones in both protein and mRNA levels (P=.0489 and P=.0446, respectively). CONCLUSION: The current study provides a rationale to plan a randomized trial to compare the efficacy of S-1 according to the HPV status in OPCs.

Factors affecting outcomes of alternating chemoradiotherapy for nasopharyngeal cancer.

OBJECTIVE: Nasopharyngeal cancer (NPC) is radiosensitive and chemosensitive. We evaluated the efficacy of alternating chemoradiotherapy in patients with advanced NPC. METHODS: Alternating chemoradiotherapy was initiated in 30 patients with NPC, and 27 patients with cancer stages II (n = 6), III (n = 8), IVA (n = 9), and IVB (n = 4) were retrospectively analyzed. Chemotherapy was initially administered followed by radiotherapy, and chemotherapy, radiotherapy, and chemotherapy were alternately administered. Of the 27 patients, 22 patients received cisplatin (50 mg/m2/day, days 6 and 7) and 5-fluorouracil (5-FU; 800 mg/m2/day, days 1-5), whereas 5 patients received carboplatin (AUC 4-5, day 6) and 5-FU. RESULTS: Of the 27 patients, 19 (70%) received 3 chemotherapy courses. The total duration of alternating chemoradiotherapy was 81 to 101 days (median, 90 days). At a median follow-up of 53 months, the 5-year progression-free survival (PFS) was 71%. Multivariate analysis showed that weight loss and the number of chemotherapy courses had a significant effect on PFS. CONCLUSION: Alternating chemoradiotherapy led to similar or higher survival rates compared with concurrent chemoradiotherapy, which was characterized by good compliance and adaptable intensity.

Intraoperative free jejunum flap monitoring with indocyanine green near-infrared angiography.

The free jejunum flap technique has been regarded as the optimal approach during circumferential pharyngolaryngectomy reconstruction. Although classical patency tests are available, an intraoperative guarantee of the patency of anastomoses and microcirculations is inevitable. Indocyanine green near-infrared angiography (ICGA) was intraoperatively performed in six patients after reconstruction using the free jejunum flap. An adequate arterial as well as venous phase was observed. In addition to classical patency tests and doppler, we have successfully monitored the flap after total pharyngolalyngectomy intraoperatively using the ICGA. Our preliminary results implicate that this novel technique offers secure intraoperative monitoring of a free jejunum graft. This technique will provide us with advantages over regular patency test in selected cases.

Association of 18F- fluorodeoxyglucose uptake with the expression of metabolism-related molecules in papillary thyroid cancer.

OBJECTIVES: 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) is a diagnostic imaging method that is based on the Warburg effect, which is the increased uptake of glucose through aerobic glycolysis in cancer cells. The diagnostic value of 18F-FDG-PET/CT for thyroid cancer is controversial. However, uptake of 18F-FDG and the corresponding maximum standardized uptake value (SUVmax) is expected to reflect the metabolic status of cancer cells. In the present study, we sought to determine the relationship between 18F-FDG uptake and tumor metabolism- associated factors. METHODS: This was a single-center retrospective study. In the present study, SUVmax was compared with the expression of hexokinase 2 (HK2), glucose transporter 1 (GLUT1), vascular endothelial growth factor (VEGF), and glutaminase 1 (GLS1) in 41 patients with thyroid cancer. RESULTS: GLS1 expression was found to be moderately correlated with SUVmax (p < 0.001, r = 0.51), whereas HK2 and VEGF expression were weakly correlated (p = 0.011, r = 0.28, p = 0.008, r = 0.29, respectively) and GLUT1 did not correlate with SUVmax (p = 0.62, r = 0.06). CONCLUSION: Our findings suggest 18F-FDG PET/CT reflects GLS1 expression in thyroid cancer and could be used to select suitable candidates for GLS1 inhibitor treatment.

Lymph node metastasis regulation by peritumoral tonsillar tissue mitochondria-related pathway activation in oropharyngeal cancer.

Immune-related gene expression profiles of peritumoral tonsillar tissues are modified by oropharyngeal cancer (OPC) nodal status. This study explored immunometabolism and immune cell count alterations in peritumoral tonsillar tissue according to OPC nodal status. Microarray data analysis of 27 peritumoral tonsillar tissue samples, using a newly generated mitochondrial metabolism-related gene set comprised of 948 genes, detected 228 differentially expressed genes (DEGs) (206 up- and 22 downregulated) in metastasis-negative cases compared to metastasis-positive ones. REACTOME pathway analysis of the 206 upregulated genes revealed the Toll-like receptor 4 cascade were most enriched. Immune cell proportion analysis using the CIBERSORTx algorithm revealed a significantly higher rate of naïve B cells, but lower rates of regulatory T cells and resting natural killer cells in metastasis-negative cases. Digital spatial profiling of the 6 OPC tissues detected 9 DEGs in the lymphoid regions, in contrast, no DEGs were identified in tumor regions according to nodal status. Cancer cell nests and pair matched normal epithelia mitochondrial DNA (mtDNA) from 5 OPC tissues were analyzed by next generation sequencing for variant detection. However, no significant mtDNA variation was found. This study identified mitochondria-related immune cell transcriptional programs and immune cell profiles associated with OPC lymphatic spread in peritumoral tonsil tissue, further evaluation of which will elucidate targetable immune mechanisms associated with OPC lymphatic dissemination.

Tumor-targeted chemotherapy with the nanopolymer-based drug NC-6004 for oral squamous cell carcinoma.

Cisplatin (CDDP) has been a key drug for chemotherapy in patients with head and neck squamous cell carcinoma. Nephrotoxicity is one of its adverse reactions that are dose limiting. To increase its antitumor effects and reduce such toxicity problems, polymeric micelles carrying CDDP (NC-6004) have been developed. The present study was designed to evaluate the efficacy and safety of NC-6004 for oral squamous cell carcinoma. In vitro antitumor activity was assayed in four oral squamous cell carcinoma cell lines. To investigate the antitumor and nephrotoxic effects of NC-6004, nude mice bearing OSC-19 were administered NC-6004 or CDDP. The in vitro growth-inhibitory effect of NC-6004 was significantly less than that of CDDP. However, both NC-6004 and CDDP showed equivalent antitumor effects in vivo. Mice with CDDP developed renal cell apoptosis; however, those injected with NC-6004 were almost free of renal cell injury. Moreover, in an orthotopic tongue cancer model using OSC-19, NC-6004 reduced the rate of sentinel lymph node metastasis to lower than that with CDDP. In conclusion, considering the potential advantages in terms of noticeable antitumor activity, lymphatic drug delivery and reduced nephrotoxicity, NC-6004 represents a significant structural improvement in the development of a platinum complex.