Anthony Po Wing Yuen

Mature miR-184 as Potential Oncogenic microRNA of Squamous Cell Carcinoma of Tongue

Purpose: The aim of this study was to evaluate the microRNA expression patterns in squamous cell carcinoma (SCC) of the tongue. Experimental Design: Expression levels of 156 human mature microRNAs were examined using real-time quantitative PCR (Taq Man MicroRNA Assays; Human Panel) on laser microdissected cells of 4 tongue carcinomas and paired normal tissues. Expression of mature miR-184 was further validated in 20 paired tongue SCC and the normal tissues. Potential oncogenic functions of miR-184 were evaluated in tongue SCC cell lines (Cal27, HN21B, and HN96) with miR-184 inhibitor. Plasma miR-184 levels were evaluated using real-time quantitative PCR. Results: Using 3-fold expression difference as a cutoff level, we identified 24 up-regulated mature miRNAs including miR-184, miR-34c, miR-137, miR-372, miR-124a, miR-21, miR-124b, miR-31, miR-128a, miR-34b, miR-154, miR-197, miR-132, miR-147, miR-325, miR-181c, miR-198, miR-155, miR-30a-3p, miR-338, miR-17-5p, miR-104, miR-134, and miR-213; and 13 down-regulated mature miRNAs including miR-133a, miR-99a, miR-194, miR-133b, miR-219, miR-100, miR-125b, miR-26b, miR-138, miR-149, miR-195, miR-107, and miR-139. Overexpression of miR-184 was further validated in 20 paired tongue SCC and normal tissues (P = 0.002). Inhibition of miR-184 in tongue SCC cell lines could reduce cell proliferation rate. Down-regulation of c-Myc was observed in two cell lines in response to miR-184 inhibitor. Suppressing miR-184 could induce apoptosis in all three cell lines. Plasma miR-184 levels were significantly higher in tongue SCC patients in comparison with normal individuals, and the levels were significantly reduced after surgical removal of the primary tumors. Conclusions: Overexpression of miR-184 might play an oncogenic role in the antiapoptotic and proliferative processes of tongue SCC. In addition, plasma miR-184 levels were associated with the presence of primary tumor. Further studies on the aberrantly expressed miRNAs in tongue SCC as well as using plasma miRNAs as novel tumor markers are warranted.

Twist Overexpression Correlates with Hepatocellular Carcinoma Metastasis through Induction of Epithelial-Mesenchymal Transition

Purpose: Hepatocellular carcinoma (HCC) is a rapidly growing tumor associated with a high propensity for vascular invasion and metastasis. Epithelial-mesenchymal transition (EMT) is a key event in the tumor invasion process. Recently, Twist has been identified to play an important role in EMT-mediated metastasis through the regulation of E-cadherin expression. However, the actual role of Twist in tumor invasiveness remains unclear. The purpose of this study is to investigate the expression and possible role of Twist in HCC. Experimental Design: We evaluated Twist and E-cadherin expression in HCC tissue microarray of paired primary and metastatic HCC by immunohistochemical staining. The role of Twist in EMT-mediated invasiveness was also evaluated in vitro in HCC cell lines. Results: We first showed that overexpression of Twist was correlated with HCC metastasis (P = 0.001) and its expression was negatively correlated with E-cadherin expression (P = 0.001, r = −0.443) by tissue microarray. A significant increase of Twist at the mRNA level was also found in metastatic HCC cell lines MHCC-97H, MHCC-97L, and H2M when compared with nonmetastatic Huh-7, H2P, and PLC cell lines. The MHCC-97H cell line, which has a higher metastatic ability, was found to have a higher level of Twist than MHCC-97L. Accompanied with increased Twist expression in the metastatic HCC cell lines when compared with the nonmetastatic primary ones, we found decreased E-cadherin mRNA expression in the metastatic HCC cell lines. By ectopic transfection of Twist into PLC cells, Twist was able to suppress E-cadherin expression and induce EMT changes, which was correlated with increased HCC cell invasiveness. Conclusion: This study shows that Twist overexpression was correlated with HCC metastasis through induction of EMT changes and HCC cell invasiveness.

Prognostic factors of clinically stage I and II oral tongue carcinoma—A comparative study of stage, thickness, shape, growth pattern, invasive front malignancy grading, martinez‐gimeno score, and pathologic features

This study aims at evaluation of the different prognostic models, including stage, tumor thickness, shape, malignancy grading of tumor invasive front, Martinez‐Gimeno score, and pathologic features in the prediction of subclinical nodal metastasis, local recurrence, and survival of early T1 and T2 oral tongue squamous cell carcinoma. The results will have important implication for the management of patients.

Elective neck dissection versus observation in the treatment of early oral tongue carcinoma

The aim of the present review is to evaluate the results of elective neck dissection and “watchful waiting” in the surgical treatment of stages I and II squamous cell carcinoma of oral tongue.

Salvage of recurrent head and neck squamous cell carcinoma after primary curative surgery

The efficacy of salvage treatment of recurrent head and neck squamous cell carcinomas (HNSCC) after primary curative surgery was evaluated.

A comparison of the prognostic significance of tumor diameter, length, width, thickness, area, volume, and clinicopathological features of oral tongue carcinoma

BACKGROUND The present study aims at evaluation of the prognostic value of tumor size including diameter, length, thickness, width, area, and volume in the prediction of nodal metastasis, local recurrence, and survival of oral tongue carcinoma. The results will have important implications for the management of patients. METHODS Eighty-five glossectomy specimens of oral tongue carcinoma were serially sectioned in 3 mm thickness for the tumor size evaluation with computer image analyzer. RESULTS Among all the tumor size parameters being evaluated, tumor thickness was the only significant factor for the prediction of local recurrence, nodal metastasis, and survival. With the use of 3 mm and 9 mm division, tumor of up to 3 mm thickness has 10% nodal metastasis, 0% local recurrence, and 100% 5-year actuarial disease-free survival; tumor thickness of more than 3 mm and up to 9 mm has 50% nodal metastasis, 11% local recurrence, and 77% 5-year actuarial disease free survival; tumor of more than 9 mm has 65% nodal metastasis, 26% local recurrence, and 60% 5-year actuarial disease-free survival. CONCLUSIONS Tumor thickness should be considered in the management of patients with oral tongue carcinoma.

Identification of pyruvate kinase type M2 as potential oncoprotein in squamous cell carcinoma of tongue through microRNA profiling

MicroRNAs (miRNAs) are noncoding RNAs with specific regulatory role in gene expression. Recent reports suggested their involvement in human malignancies. Currently, there is no information concerning miRNA expression and functions in squamous cell carcinoma (SCC) of tongue. In this study, we evaluated the expression patterns of 156 mature miRNAs in tongue SCC using Taqman‐based microRNA assays. Of these 156 miRNAs, miR‐133a and miR‐133b were significantly reduced in tongue SCC cells in comparison with the paired normal epithelial cells. Tongue SCC cell lines transfected with miR‐133a and miR‐133b precursors displayed reduction in proliferation rate. In addition, the number of apoptotic cells was increased in response to the introduction of precursors. Computational target gene prediction suggested that both miR‐133a and miR‐133b are targeting transcript of pyruvate kinase type M2 (PKM2), a potential oncogene in solid cancers. In tongue SCC cell lines, PKM2 expression was reduced in response to miR‐133a and miR‐133b precursors transfection. Immunohistochemical staining results of tongue SCC tissues suggested that PKM2 was overexpressed in tongue SCC and was associated with the downregulation of miR‐133a and miR‐133b. Our results suggested that aberrant reduction of miR‐133a and miR‐133b was associated with the dysregulation of PKM2 in SCC of tongue.

Clinicopathological analysis of elective neck dissection for N0 neck of early oral tongue carcinoma

BACKGROUND The study aims at evaluation of the efficacy of elective neck dissection as a staging and therapeutic procedure for N0 neck of early carcinoma of the oral tongue by whole organ serial sectioning. METHODS There were 50 stage I and II patients. The neck dissection specimens were whole organ sectioned in 3-mm intervals for the evaluation of nodal metastasis. RESULTS There were 18 (36%) patients with subclinical nodal metastasis. The total number of metastatic nodes were 31 (1%) among all 2,826 nodes being examined. The metastatic foci had a median size of 3 mm and occupied a median of 6% of the cross sectional area of the involved nodes. The ipsilateral level II nodes were the commonest (26%) site of metastasis. Metastatic nodes were present in 34% patients who had negative preoperative radiological assessment and in 20% patients who had negative intraoperative frozen section sampling of neck nodes. Patients with subclinical nodal metastasis had a high incidence of regional recurrence (62%) and low survival (27%) when postoperative radiotherapy was not given after elective neck dissection. CONCLUSIONS Ipsilateral level I,II,III neck dissection is an adequate diagnostic procedure for staging of the N0 neck of early oral tongue carcinoma. Its diagnostic role cannot be replaced by the available pre-operative radiological screening and intra-operative frozen section sampling. However, elective selective neck dissection is an effective but not adequate therapeutic procedure, and post-operative adjuvant radiotherapy and chemotherapy have to be considered for all pathologically positive necks.

Prospective randomized study of selective neck dissection versus observation for N0 neck of early tongue carcinoma

There are controversies on the benefits of elective neck dissection (END) for oral tongue carcinoma.

Loss of E-cadherin expression resulting from promoter hypermethylation in oral tongue carcinoma and its prognostic significance

E‐cadherin is expressed on the surface of normal epithelial cells. Loss of E‐cadherin expression has been found in cancers and is postulated to facilitate tumor cell dissociation and metastasis. This study evaluated the role of promoter dense methylation in the downregulation of E‐cadherin expression in oral tongue carcinoma.