Survivin expression in oral squamous cell carcinoma

A series of 110 cases of oral squamous cell carcinoma (SCC) together with six lymph node and one distant metastatic lesions was analysed for expression of survivin, a recent apoptosis inhibitor, by immunohistochemistry and Western blotting. In total, 91 cases (82.7%) of carcinoma and all metastasis (seven cases, 100%) were positive for survivin expression, with weighted survivin scores ranging from 1 to 4. In contrast, normal oral epithelium did not express survivin. There was no significant correlation between survivin expression and age, sex, tumour size, the presence of lymph node and distant metastases. Survivin expression was increased in poorly differentiated tumours, even if differences were not statistically significant. In contrast, when analysed for prognostic significance, patients with low survivin expression had statistically significant better survival rates than the group with high survivin expression (P<0.05). These data suggest that survivin expression may identify cases of oral SCC with more aggressive and invasive phenotype.     

Characterization of autofluorescence in oral squamous cell carcinoma

This study was carried out to evaluate the clinical characteristics of autofluorescence in oral squamous cell carcinoma (SCC) and analyze the fluorescent substances using high-performance liquid chromatography (HPLC). Fifty of 55 oral SCCs (91%) emitted orange or red fluorescence, which was recorded by fluorescence photography. The intensity of the fluorescence significantly correlated with the T and N categories of the cancers, but did not show statistical difference for the types of clinical appearance and primary sites. Protoporphyrin and coproporphyrin were identified as the fluorescent substance in the SCC samples, and the elution patterns on HPLC revealed some porphyrin compounds as specific to oral cancer. These results suggest that the autofluorescence in oral SCC correlates with the progression of lesions, and that fluorescent substances such as protoporphyrin are produced in association with the cancerous tissue.     

Cytokeratin alteration in oral leukoplakia and oral squamous cell carcinoma

Intermediate filaments are involved in cell migration and intracellular signal transduction pathways. In a variety of organs, the expression of distinct intermediary filaments are further associated with distinct steps of malignant transformation. In this study, we seeked to define the cytokeratin (Ck) expression pattern in oral leukoplakia and oral squamous cell carcinoma (OSCC). One hundred and ninety-two patients with OSCC, 117 patients with oral leukoplakia without dysplasia (OL) and 23 with oral leukoplakia with dysplasia (squamous intraepithelial neoplasia) (OLD) of the oral cavity were investigated for the immunohistochemical expression of Ck 5-6, Ck 8/18, Ck 1 Ck 10, Ck 14, Ck 19 using the tissue microarray technique. Correlations between clinical features and the expression of cytokeratins were evaluated statistically by chi2 tests. The expression of Ck 8/18, Ck 19 and Ck 1 was seen in 3.1% (Ck 8/18), 12.5% (Ck 19), 75.4% (Ck 1) of all leukoplakias, 1.0% (Ck 8/18), 9.4% (Ck 19), 76.8% (Ck 1) in OL, 13.0% (Ck 8/18), 27.3% (Ck 19), 68.4% (Ck 1) in OLD and was significantly associated with the degree of dysplasia (Ck 8/18 p<0.01; Ck 19 p<0.01; Ck 1 p<0.01) and the acquisition of invasive growth properties. The highest frequencies were observed in invasive squamous cell carcinomas. The expression of Ck 8/18 and Ck 19 in transformed oral lesions can be regarded as an early feature in the pathogenesis of invasive OSCC. However, the aberrant expression of Ck 8/18 and Ck 19 in an even higher frequency in invasive carcinomas characterizes the expression of typical glandular cytokeratins as a general progression marker in squamous cell carcinomas. These results can be interpreted as first hints that oral leukoplakias with an expression of Ck 8/18 or 19 independent of dysplasia, should be resected totally since they might indicate an increased progression potential.     

Tenascin-C matrix assembly in oral squamous cell carcinoma

We previously showed that the extracellular matrix component tenascin-C (TN-C) is upregulated in oral squamous cell carcinoma (SCC) compared with the normal oral mucosa. In this study we examined oral biopsy specimens of mild to moderate dysplasia or carcinoma in situ to study TN-C expression. We found that carcinoma in situ is the stage at which TN-C becomes widely expressed, suggesting it may be involved in the initial stages of tumor progression. To study TN-C matrix production in vitro, we used an invasive oral SCC cell line (HSC-3) and peri-tumor fibroblasts (PTF). Neither cell type organized a TN-C matrix when cultured alone; however, when co-cultured with HSC-3 cells, PTF were able to assemble a TN-C matrix. PTF retained the ability to organize a TN-C matrix when separated from the HSC-3 cells by a semi-permeable membrane, indicating that cell-cell contact is not necessary for TN-C matrix organization and suggesting that soluble factors may be involved. Moreover, PTF were induced to assemble TN-C matrices when grown in medium conditioned by both the PTF and HSC-3 cells. Antibodies to fibronectin (FN) and to the first FN type III repeat blocked both FN and TN-C matrix assembly, indicating that TN-C matrix organization is dependent on an FN template. Antibodies to α5, αv and β1 integrins also blocked TN-C matrix formation. When seeded onto FN matrices, the co-cultures were unaffected by the anti-integrin and anti-FN antibodies and were able to organize a TN-C matrix. Our results suggest that progression of malignant oral SCC is accompanied by an alteration of the normal ECM to one rich in TN-C, and that the organization of a TN-C matrix is dependent on soluble cues provided by both the SCC cells and the PTF. Int. J. Cancer 75:680–687, 1998.© 1998 Wiley-Liss, Inc.     

Thymidine phosphorylase expression in oral squamous cell carcinoma

Thymidine phosphorylase (TP), as an enzyme involved in DNA synthesis, catalyzes the reversible conversion of thymidine to thymine. It is also identical to the angiogenic factor, platelet-derived endothelial cell growth factor. We examined TP expression using immunohistochemistry in 66 archival samples obtained from the patients with primary oral squamous cell carcinoma (SCC) and investigated its relation to tumor vascularity, cell proliferation, apoptosis, clinicopathological features and survival. TP expression was identified in cytonucleus and/or cytoplasm in carcinomas, but was not identified in histologically normal epithelia distant to tumor in most cases. No significant difference of microvessel density (MVD) was found between the carcinomas with high TP expression (H-TP) and low TP expression (L-TP). The percentages of proliferative cells marked by Ki-67 staining in H-TP carcinomas was significantly higher than that in L-TP carcinomas (P=0.0222). The apoptotic indice (AI) in H-TP carcinomas tended to be lower than that in L-TP carcinomas (P=0.0723). Moreover, the level of TP expression was significantly correlated the pattern of tumor invasion (P=0.0146) and marginally correlated with lymph nodal metastasis (P=0.0804). Our results suggested that TP enzyme may play a role in promotion of tumor growth in oral SCC, and that its expression can be indicative of tumor aggressiveness in this tumor type.     

Bag-1 proteins in oral squamous cell carcinoma

Bag-1 is an anti-apoptotic protein that exhibits altered expression in many malignancies, including oral squamous cell carcinoma. The bag-1 gene gives rise to different protein products with different subcellular localisations through alternative translational initiation sites. In oral squamous cell carcinoma, cytoplasmic expression has been associated with metastasis to regional lymph nodes and poor prognosis. In contrast, the longest Bag-1 isoform is nuclear and may regulate differentiation in oral epithelium. In this review, the functions of the three isoforms of Bag-1 expressed in oral epithelial cells are discussed in relation to their contribution to oral carcinogenesis.     

Sentinel node biopsy in oral squamous cell carcinoma

The clinical utility of sentinel node biopsy techniques for cutaneous melanoma has led multiple investigators to study the applicability of this approach to other solid tumors, including cancers of the upper aerodigestive tract, and especially the oral cavity. Preliminary data indicate that it may be useful for early oral cancers, with the exception of floor of mouth tumors, where technical challenges related to the proximity of the lymphatic basin remain a problem. A multi-institutional pathologic validation trial, involving sentinel node biopsy followed by completion selective neck dissection, has completed accrual. While central step sectioning and immunohistochemistry remain to be completed and analyzed, routine pathologic techniques provided negative predictive values of 96% for oral cancer excluding floor of mouth lesions. Subsequent trials need to involve clinical follow-up and evaluation for recurrence in the neck. We believe this technique may ultimately play a role in the management of early oral cancer.     

Mitochondrial DNA mutations in oral squamous cell carcinoma

It has previously been demonstrated that mitochondrial DNA (mtDNA) mutations within the ND2 gene of histologically normal parotid salivary gland tissue of smokers may be molecular biomarkers for smoking-induced mtDNA damage. Oral squamous cell carcinoma (SCC) is strongly related to cigarette smoking; therefore, we used PCR and direct sequencing to establish whether mtDNA mutations were also present in oral SCC which could be used as additional biomarkers for smoking-associated DNA damage. In addition to searching for mutations in the ND2 gene, the mitochondrial D-Loop was also analysed. Three mutation hotspots were observed in the D-Loop at nt 146, 152 and 186, two of which (nt 146 and 152) have also been implicated in oesophageal SCC, another smoking-related cancer. The mutation hotspot observed at nt 186 has not previously been reported in other tumours. Furthermore, we show that the mutations previously reported within the ND2 gene in normal parotid tissue of smokers were not evident in these samples, but that a mutation hotspot occurs at nucleotide 4917 in oral SCC. We also show that D-Loop mutations occur predominantly in male smokers and female non-smokers and that this association with gender is statistically significant (P = 0.003). We conclude that the mtDNA mutation hotspots found in this study, in particular nt 186, are potential biomarkers for oral SCC. However, owing to gender-specific differences in occurrence in smokers and non-smokers, and a lack of environmental smoking history, in general, it is difficult to associate these mutations with mtDNA damage induced by smoking. If the mutations observed in the subset of male patients are smoking induced, given our previous findings, mutation hotspots in the ND2 gene may be tissue specific suggesting the causative mutagens for mtDNA damage within these tissues are likely to be different.     

Diagnosis and therapy of oral squamous cell carcinoma

Oral squamous cell carcinoma ranks among the top ten most common cancers worldwide. Despite the success in diagnosis and therapy during the past 30 years, oral squamous cell carcinoma still belongs to the tumor types with a very unfavorable prognosis. In an effort to identify genomic alterations with prognostic relevance, we applied the comparative genomic hybridization technique on oral squamous cell carcinoma. The tumors exhibited from five up to 47 DNA copy number alterations, indicating a considerable degree of genomic imbalance. Out of 35 tumors, 19 showed a gain of chromosome band 7p12. Genomic imbalances were investigated by hierarchical cluster analysis and clustered image mapping to investigate whether genomic profiles correlate with clinical data. Results of the present investigation show that profiling of genomic imbalances in general, and especially of the epidermal growth factor receptor (EGFR) on 7p12, may be suitable as prognostic factors. In order to identify small-molecule inhibitors for EGFR, we established a database of 531 natural compounds derived from medicinal plants used in traditional Chinese medicine. Candidate compounds were identified by correlation analysis using the Kendall tau-test of IC50 values of tumor cell lines and microarray-based EGFR mRNA expression. Further validation was performed by molecular docking studies using the AutoDock program with the crystal structure of EGFR tyrosine kinase domain as docking template. We estimate these results will be a further step toward the ultimate goal of individualized, patient-adapted tumor treatment based on tumor molecular profiling.     

Expression of emmprin by oral squamous cell carcinoma

A transmembrane glycoprotein recently identified on some tumor cells, extracellular matrix metalloproteinase inducer (EMMPRIN), has been shown to induce metalloproteinase (MMP) production by peritumor fibroblasts (PTF). We examined biopsy specimens of normal human oral mucosa and oral squamous cell carcinoma (SCC) for expression of EMMPRIN. In normal mucosa, EMMPRIN was expressed at the cell membrane throughout the epithelium with a slight enhancement along the basal cell layer. In oral SCC, EMMPRIN was expressed at the cell membrane throughout the entire lesion. Immunofluorescence microscopy localized EMMPRIN to the cell membrane in a highly invasive oral SCC cell line in agreement with our in vivo observations. Function-blocking antibodies to EMMPRIN significantly inhibited oral SCC cell migration on tenascin-C (TN-C) and fibronectin as well as invasion through a reconstituted basement membrane (RBM). We previously showed that soluble factors from SCC cells and PTF are required for deposition of a TN-C matrix. To determine whether EMMPRIN may modulate the release or expression of these soluble factors, we again used function-blocking antibodies. Antibodies to EMMPRIN completely inhibited the organization of TN-C matrices and partially reduced the deposition of FN matrices by oral SCC cell /PTF co-cultures. In addition, antibodies to EMMPRIN perturbed the expression of MMP-2. Moreover, antibodies to MMP-2 perturbed oral SCC cell invasion of an RBM by approx. 75%. Our results demonstrate that EMMPRIN is highly expressed in oral SCC, facilitates tumor cell motility, and mediates TN-C matrix deposition. Taken together, these results suggest that EMMPRIN may help regulate oral squamous cell carcinoma invasion.     

Histopathological prognosticators in oral and oropharyngeal squamous cell carcinoma

Histopathological assessment of the surgical resection specimen continues to provide information that is central to determining the post-operative treatment needs and prognosis for an individual patient with oral/oropharyngeal squamous cell carcinoma. This review describes the prognostic value of histopathological features related to the primary tumour and the cervical lymph nodes, and considers their relative merits. In addition, a brief overview of more general patient factors is included. Throughout the review, guidance is offered on practical aspects of the histopathological assessment together with brief mention of potential inaccuracies. Emphasis is given also to the importance of the partnership between the surgeon and the pathologist, the need for standardisation during all stages of the histopathological assessment, and the value of accurate documentation of the findings.     

Stathmin guides personalized therapy in oral squamous cell carcinoma

The survival benefit from docetaxel, cisplatin and 5‐fluorouracil (TPF) induction chemotherapy in oral squamous cell carcinoma (OSCC) patients is not satisfactory. Previously, we identified that stathmin, a microtubule‐destabilizing protein, is overexpressed in OSCC. Here, we further investigated its role as a biomarker that impacts on OSCC chemosensitivity. We analyzed the predictive value of stathmin on TPF induction chemotherapy and its impact on OSCC cell chemosensitivity. Then, we further investigated the therapeutic effects of the combination therapy of TPF chemotherapy and PI3K‐AKT‐mTOR inhibitors in vitro and in vivo. We found that OSCC patients with low stathmin expression benefited from TPF induction chemotherapy, while OSCC patients with high stathmin expression could not benefit from TPF induction chemotherapy. Stathmin overexpression promoted cellular proliferation and decreased OSCC cell sensitivity to TPF treatment. In addition, inhibition of the PI3K‐AKT‐mTOR signaling pathway decreased stathmin expression and phosphorylation. The combination therapy of TPF chemotherapy and PI3K‐AKT‐mTOR inhibitors exhibited a potent antitumor effect both in vitro and in vivo. Therefore, stathmin can be used as a predictive biomarker for TPF induction chemotherapy and a combination therapy regimen based on stathmin expression might improve the survival of OSCC patients.     

口腔鳞状细胞癌中上皮-间充质转化相关影响因素的研究进展

口腔鳞状细胞癌是最常见的头颈部恶性肿瘤。近年来,上皮－间充质转化（epithelial-mesenchymal transition,EMT）在肿瘤研究方面一度成为新的研究热点,EMT是由上皮细胞表型向间充质细胞表型转变的过程,在这个过程中,可促进癌细胞的侵袭,进而完成肿瘤的转移,影响患者的预后。本文综合目前的研究,对近年来口腔鳞状细胞癌在EMT方面的细胞因子、通路、RNA、细菌病毒微生物和微环境等相关影响因素进行综述。     

Promoter hypermethylation in Indian primary oral squamous cell carcinoma

We evaluated promoter hypermethylation of a panel of tumor suppressor genes as a means to detect epigenetic alterations in oral squamous cell carcinomas (OSCC) of Indian‐origin and compare with North‐American head and neck squamous cell carcinomas (HNSCC). Quantitative‐methylation‐specific PCR was used to investigate the promoter methylation status of DCC, EDNRB, p16^INK4a and KIF1A in 92 OSCC, and compared to 48 paired normal tissues and 30 saliva and sera samples from healthy control subjects. Aberrant methylation of at‐least one of these genes was detected in 74/92 (80.4%) OSCC; 72.8% at EDNRB, 71.7% at KIF1A, 47.8% at p16^INK4a and 58.7% at DCC; and in 5 of 48 (10.4%) normal oral tissues. None of the saliva and sera samples from controls exhibited DNA methylation in these four target genes. Thirty‐two of 72 node positive cases harbored p16^INK4a and DCC hypermethylation (p = 0.005). Thus, promoter hypermethylation in genes analyzed herein is a common event in Indian OSCC and may represent promising markers for the molecular staging of OSCC patients. We found higher frequency of p16^INK4a methylation (47.8%) in this Indian cohort in comparison with a North‐American cohort (37.5%). In conclusion, aberrant methylation of EDNRB, KIF1A, DCC and p16^INK4a genes is a common event in Indian OSCC, suggesting that epigenetic alterations of these genes warrant validation in larger studies for their potential use as biomarkers.