Prognostic value of radiological T category using conventional MRI in patients with oral tongue cancer: comparison with pathological T category

PURPOSE

This study aimed to compare the radiological tumor (T)-category using multiparametric MRI with the pathological T category in patients with oral tongue squamous cell carcinoma (OTSCC) and to examine which is a better predictor of prognosis.

METHODS

This retrospective study included 110 consecutive patients with surgically resected primary OTSCC who underwent preoperative contrast-enhanced MRI. T categories determined by maximum diameter and depth of invasion were retrospectively assessed based on the pathological specimen and multiparametric MRI. The MRI assessment included the axial and coronal T1-weighted image (T1WI), axial T2-weighted image (T2WI), coronal fat-suppressed T2WI, and axial and coronal fat-suppressed contrast-enhanced T1WI (CET1WI). Axial and coronal CET1WI measurements were divided into two groups: measurements excluding peritumoral enhancement (MEP) and measurements including peritumoral enhancement. The prognostic values for recurrence and disease-specific survival after radiological and pathological T categorization of cases into T1/T2 and T3/T4 groups were compared.

RESULTS

The T category of MEP on coronal CET1WI was the most relevant prognostic factor for recurrence [hazard ratio (HR) = 3.30, p = 0.001] and the HR was higher than the HR for pathological assessment (HR = 2.26, p = 0.026). The T category determined by MEP on coronal CET1WI was also the most relevant prognostic factor for disease-specific survival (HR = 3.12, p = 0.03), and the HR was higher than the HR for pathological assessment (HR = 2.02, p = 0.20).

CONCLUSION

The T category determined by MEP on the coronal CET1WI was the best prognostic factor among all radiological and pathological T category measurements.

Genome-wide DNA methylation profiling in tongue squamous cell carcinoma

OBJECTIVES

To provide a comprehensive characterization of DNA methylome of oral tongue squamous cell carcinoma (OTSCC) and identify novel tumor-specific DNA methylation markers for early detection using saliva.

MATERIAL AND METHODS

Genome-wide DNA methylation analysis including six OTSCC matched adjacent non-tumoral tissue and saliva was performed using Infinium MethylationEPIC array. Differentially methylated levels of selected genes in our OTSCC cohort were further validated using OTSCC methylation data from The Cancer Genome Atlas database (TCGA). The methylation levels of a set of tumor-specific hypermethylated genes associated with a downregulated expression were evaluated in saliva. Receiver operating characteristic (ROC) curves were performed to assess the diagnostic value of DNA methylation markers.

RESULTS

A total of 25,890 CpGs (20,505 hypomethylated and 5385 hypermethylated) were differentially methylated (DMCpGs) between OTSCC and adjacent non-tumoral tissue. Hypermethylation of 11 tumor-specific genes was validated in OTSCC TCGA cohort. Of these 11 genes, A2BP1, ANK1, ALDH1A2, GFRA1, TTYH1, and PDE4B were also hypermethylated in saliva. These six salivary methylated genes showed high diagnostic accuracy (≥0.800) for discriminating patients from controls.

CONCLUSIONS

This is the first largest genome-wide DNA methylation study on OTSCC that identifies a group of novel tumor-specific DNA methylation markers with diagnostic potential in saliva.

WEE1 kinase inhibitor MK-1775 sensitizes oral tongue squamous cell carcinoma cells to radiation irrespective of TP53 status

OBJECTIVE

Oral tongue squamous cell carcinoma (OTSCC) frequently harbors non-functional p53 and depends on G2/M checkpoint mediated by WEE1. WEE1 suppression has been identified as a promising anti-tumor strategy. This study investigated the capacity of WEE1 kinase inhibitor (MK-1775) and its underlying mechanisms in enhancing radiation responses of OTSCC cells in vitro.

MATERIALS AND METHODS

WEE1 kinase expression and its downstream target (CDK1) were investigated in OTSCC versus normal oral tissue. A synergistic combination of MK-1775 with radiation on OTSCC cell lines with different p53 statuses was assessed by viability assay. The radio-sensitizing effects of MK-1775 on apoptosis, cell cycle, DNA damage, and mitotic entry were also determined.

RESULTS

Irradiation enhanced CDK1 expression in all tested cell lines, though the effect was far more pronounced in p53 mutated cell lines. MK-1775 exhibited inhibitory effects against the survival of all cell lines and enhanced their response to the radiation. These effects were strongly elicited by induction of apoptosis and lethal mitosis, but less likely by abrogation of radiation-induced G2 arrest.

CONCLUSION

These results demonstrate the efficacy of MK-1775 in enhancing the radiation effect on OTSCC in vitro associated with a significant apoptotic death rate, identifying WEE1 inhibitor as a potent radiosensitizer in OTSCC irrespective of p53 mutational status.

Loss of Caveolin-1 Expression in Tumor Cells is Associated with Increased Aggressiveness and Cell Invasion in Oral Squamous Cell Carcinoma

BACKGROUND

Changes in Caveolin-1 (CAV-1) expression are related to tumorigenesis. The aim of this study was to evaluate the role of CAV-1 in tumor progression in oral squamous cell carcinoma (SCC) tissue samples and the effect of CAV-1 silencing on two oral tongue SCC (OTSCC) cell lines (SCC-25, from a primary tumor, and HSC-3 from lymph node metastases).

METHODS

Mycroarray hybridization, mRNA expression, and immunohistochemistry were performed on OSCC tissue samples and corresponding non-tumoral margin tissues. The effects of CAV-1 silencing (siCAV-1) on cell viability, membrane fluidity, on the expression of epithelial to mesenchymal transition (EMT) markers and on cell migration and invasion capacity of OTSCC cell lines were evaluated.

RESULTS

Microarray showed a greater CAV-1 expression (1.77-fold) in OSCC tumors than in non-tumoral tissues and 2.0-fold more in less aggressive OSCCs. However, significant differences in CAV-1 gene expression were not seen between tumors and non-tumoral margins nor CAV-1 with any clinicopathological parameters. CAV-1 protein was localized both in carcinoma and in spindle cells of the tumor microenvironment (TME), and CAV-1 positive TME cells were associated with smaller/more aggressive tumors, independent of the carcinoma cells' expression. Silencing of CAV-1 increased cell viability only in SCC-25 cells. It also stimulated the invasion of HSC-3 cells and increased ECAD and BCAT mRNA in these cells; however, the protein levels of the EMT markers were not affected.

CONCLUSION

Decreased expression of CAV-1 by tumor cells in OSCC and an increase in the TME were associated with increased cell invasiveness and tumor aggressiveness.

Novel human lymph node-derived matrix supports the adhesion of metastatic oral carcinoma cells

BACKGROUND

3D culture is increasingly used in cancer research, as it allows the growth of cells in an environment that mimics in vivo conditions. Metastases are the primary cause of morbidity and mortality in cancer patients, and solid tumour metastases are mostly located in lymph nodes. Currently, there are no techniques that model the pre-metastatic lymph node microenvironment in vitro. In this study, we prepared a novel extracellular matrix, Lymphogel, which is derived from lymph nodes, mimicking the tumour microenvironment (TME) of metastatic carcinoma cells. We tested the suitability of the new matrix in various functional experiments and compared the results with those obtained using existing matrices.

METHODS

We used both commercial and patient-derived primary and metastatic oral tongue squamous cell carcinoma (OTSCC) cell lines. We characterized the functional differences of these cells using three different matrices (human uterine leiomyoma-derived Myogel, human pre-metastatic neck lymph node-derived Lymphogel (h-LG), porcine normal neck lymph node-derived Lymphogel (p-LG) in proliferation, adhesion, migration and invasion assays. We also performed proteomic analyses to compare the different matrices in relation to their functional properties.

RESULTS

OTSCC cells exhibited different adhesion and invasion patterns depending on the matrix. Metastatic cell lines showed improved ability to adhere to h-LG, but the effects of the matrices on cell invasion fluctuated non-significantly between the cell lines. Proteomic analyses showed that the protein composition between matrices was highly variable; Myogel contained 618, p-LG 1823 and h-LG 1520 different proteins. The comparison of all three matrices revealed only 120 common proteins. Analysis of cellular pathways and processes associated with proteomes of each matrix revealed similarities of Myogel with h-LG but less with p-LG. Similarly, p-LG contained the least adhesion-related proteins compared with Myogel and h-LG. The highest number of unique adhesion-related proteins was present in h-LG.

CONCLUSIONS

We demonstrated that human pre-metastatic neck lymph node-derived matrix is suitable for studying metastatic OTSCC cells. As a whole-protein extract, h-LG provides new opportunities for in vitro carcinoma cell culture experiments.

Prediction of 5-year overall survival of tongue cancer based machine learning

OBJECTIVE

We aimed to develop a 5-year overall survival prediction model for patients with oral tongue squamous cell carcinoma based on machine learning methods.

SUBJECTS AND METHODS

The data were obtained from electronic medical records of 224 OTSCC patients at the PLA General Hospital. A five-year overall survival prediction model was constructed using logistic regression, Support Vector Machines, Decision Tree, Random Forest, Extreme Gradient Boosting, and Light Gradient Boosting Machine. Model performance was evaluated according to the area under the curve (AUC) of the receiver operating characteristic curve. The output of the optimal model was explained using the Python package (SHapley Additive exPlanations, SHAP).

RESULTS

After passing through the grid search and secondary modeling, the Light Gradient Boosting Machine was the best prediction model (AUC = 0.860). As explained by SHapley Additive exPlanations, N-stage, age, systemic inflammation response index, positive lymph nodes, plasma fibrinogen, lymphocyte-to-monocyte ratio, neutrophil percentage, and T-stage could perform a 5-year overall survival prediction for OTSCC. The 5-year survival rate was 42%.

CONCLUSION

The Light Gradient Boosting Machine prediction model predicted 5-year overall survival in OTSCC patients, and this predictive tool has potential prognostic implications for patients with OTSCC.

Relationship Between Worst Pattern of Invasion and Extranodal Extension in Oral Tongue Squamous Cell Carcinomas

BACKGROUND

Oral tongue squamous cell carcinoma (OTSCC) is a common malignancy of the oral cavity with poor survival rates. The aim of this project is to investigate the relationship between certain histopathological factors such as Worst Pattern of Invasion (WPOI) and Extranodal Extension (ENE) in patients with oral tongue squamous cell carcinoma (OTSCC) who underwent surgical resection at Loyola University Medical Center.

METHODS

This was a retrospective cohort study at a tertiary care academic medical center. All patients that underwent primary surgical resection of OTSCC between 1/1/2015 and 1/1/2022 were reviewed. Patients were identified using the Cerner CoPath Laboratory Information System.

RESULTS

A total of 82 patients met inclusion criteria and were included in the study. Higher grades of WPOI (WPOI 5) were not significantly associated with the presence of ENE in our study (P = 0.82), regardless of the presence of major or minor ENE. WPOI 5 was associated with a higher incidence of local recurrence (P = 0.011).

CONCLUSIONS

Higher grades of WPOI were not found to correlate with the presence of ENE, a common histopathological factor that is used as an important prognostic indicator in OTSCC. It is important for clinicians to consider these factors separately when determining whether a patient is high-risk and would benefit from aggressive multimodal treatment.

Prognosis of tongue squamous cell carcinoma associated with individual surgical margin and pathological features

The specific muscular structure of the tongue greatly affects margin shrinkage and tumor invasion, making the optimal surgical margin controversial. This study investigated surgical margin correlated prognosis of TSCC (tongue squamous cell carcinoma) according to margin location and its value, and the histopathologic factors which are suggestive of tumor invasion. And we would like to propose defining of the surgical margin for TSCC via prognosis according to location and margin values. We reviewed 45 patients diagnosed with TSCC who visited Seoul National University Dental Hospital (SNUDH) (Seoul, Republic of Korea) from 2010 to 2019, who were managed by a single surgical team. Patient clinical and pathological data of patients were retrospectively reviewed, and in 36 out of 45 patients, the pathologic parameters including the worst pattern of invasion (WPOI) and tumor budding were investigated via diagnostic histopathology slide reading. When standardized with as 0.25 cm anterior margins, as 0.35 cm deep margin, there was no significant difference in disease specific survival (DSS) or loco-regional recurrence-free survival (LRFS). Additionally, there was a non-significant difference in DSS and LRFS at the nearest margin of 0.35 cm (PDSS=0.276, PLRFS=0.162). Aggressive WPOI and high tumor budding showed lower survival and recurrence-free survival, and there were significant differences in close margin and involved margin frequencies. In TSCC, the value and location of the surgical margin did not have a significant relationship with prognosis, but WPOI and tumor budding suggesting the pattern of muscle invasion affected survival and recurrence-free survival. WPOI and tumor budding should be considered when setting an optimal surgical margin.

Elective Neck Dissection Versus Observation in cT1-T2 Oral Tongue Squamous Cell Carcinoma: A Meta-Analysis of 11,973 Patients

The surgical management of the clinical negative neck node in early oral tongue squamous cell carcinoma (OTSCC) has been the topic of debate since few decades. As the occult cervical lymph node metastasis is considered to be the prime prognostic factor in early OTSCC, this meta-analysis has been carried out to find the risk of regional nodal recurrence, disease specific survival and overall survival rates in outcome of Elective neck dissection (END) versus patients under observation. The articles were electronically retrieved from Ovid Medline, PubMed, Cochrane and Scholar for comparison of END versus Observation in early OTSCC. The search strategy identified 37 relevant review articles from April 1979 to April 2020 from different search engines. A total of 11,973 patients from 32 retrospective analysis, 4 prospective and 1 randomised control trial were included in this meta-analysis. Statistical analysis revealed Overall test (OR: 5.31 95% CI: - 2.132-14.698) with t-test 1.919 and p value 0.113 which is not statistically significant but the readings says that there is always better Disease specific survival with END patients rather than patients kept on observation. Overall test revealed (OR: 13.02 95% CI: 1.360-17.154) with t test 2.382 and p value 0.023 which is statistically significant and showed that End significantly reduced the risk of regional nodal recurrence. Overall test revealed (OR: 7.93 95% CI: - 15.461-4.238) with t test - 1.347 and p value 0.220 which is statistically insignificant and but showed that to some extent Overall survival improves in patient with END than the patients kept on observation. This meta-analysis find that there is statistically significant relationship when Elective neck dissection was performed which reduced the risk of regional nodal recurrence. This analysis didn't statistically find any significance in Disease specific survival and Overall survival with Elective neck dissection patients rather than patients kept on observation but however showed good prognosis when elective neck dissection was performed.

Radiation modulates expression and related activities of c-Met protein in oral tongue squamous cell carcinoma cell lines

OBJECTIVES

c-Met, a receptor tyrosine kinase, is involved in the growth, invasion and metastasis of a variety of cancers. In a set of cell lines from several solid tumors, a five-fold increase in c-Met expression after irradiation has been reported. This study aimed to assess if c-Met is likewise abundantly expressed in oral tongue squamous cell carcinoma (OTSCC) upon exposure to irradiation, followed by a Met-induced biological response.

MATERIALS AND METHODS

Six OTSCC cell lines were exposed to gamma radiation doses of 2, 4, and 6 Gray. The changes in c-Met protein levels were assessed by western blot and flow cytometry. c-Met gene expression, cell migration, proliferation and cell cycle assays were performed as phenotypic readouts.

RESULTS

Irradiation resulted in upregulation of c.Met in all cell lines with different time kinetics. On average the cells displayed minimal c-Met expression on their surface ranging from 5 to 30% of total protein. Abrupt downregulation of c-Met surface expression occurred one hour after radiation but recovered 48 h post-radiation. Intracellularly, the highest level of expression was found on day 5 after radiation exposure. Irradiation induced aggressive invasive potential of the cells as determined in cell migration assays, particularly in cell lines with the highest c-Met expression.

CONCLUSIONS

These results provide novel insights into both intracellular and extracellular dynamics of c-Met expression profiles upon irradiation of OTSCC cells in vitro. It might also suggest that radiation enhances cell migration, indicative of invasiveness, through c-Met up-regulation, at least for certain types of OTSCC cells.

Nomogram based on clinical characteristics and serological inflammation markers to predict overall survival of oral tongue squamous cell carcinoma patient after surgery

BACKGROUND

Oral tongue squamous cell carcinoma (OTSCC) is a prevalent malignant disease that is characterized by high rates of metastasis and postoperative recurrence. The aim of this study was to establish a nomogram to predict the outcome of OTSCC patients after surgery.

METHODS

We retrospectively analyzed 169 OTSCC patients who underwent treatments in the Cancer Hospital of Shantou University Medical College from 2008 to 2019. The Cox regression analysis was performed to determine the independent prognostic factors associated with patient's overall survival (OS). A nomogram based on these prognostic factors was established and internally validated using a bootstrap resampling method.

RESULTS

Multivariate Cox regression analysis revealed the independent prognostic factors for OS were TNM stage, age, lymphocyte-to-monocyte ratio and immunoglobulin G, all of which were identified to create the nomogram. The Akaike Information Criterion and Bayesian Information Criterion of the nomogram were lower than those of TNM stage (292.222 vs. 305.480; 298.444 vs. 307.036, respectively), indicating a better goodness-of-fit of the nomogram for predicting OS. The bootstrap-corrected of concordance index (C-index) of nomogram was 0.784 (95% CI 0.708-0.860), which was higher than that of TNM stage (0.685, 95% CI 0.603-0.767, P = 0.017). The results of time-dependent C-index for OS also showed that the nomogram had a better discriminative ability than that of TNM stage. The calibration curves of the nomogram showed good consistency between the probabilities and observed values. The decision curve analysis also revealed the potential clinical usefulness of the nomogram. Based on the cutoff value obtained from the nomogram, the proposed high-risk group had poorer OS than low-risk group (P < 0.0001).

CONCLUSIONS

The nomogram based on clinical characteristics and serological inflammation markers might be useful for outcome prediction of OTSCC patient.

Role of plasminogen activator inhibitor-1 in oral tongue squamous cell carcinoma: An immunohistochemical and in vitro analysis

OBJECTIVE

To evaluate the influence of plasminogen activator inhibitor-1 (PAI-1) on the biological behavior and prognosis of oral tongue squamous cell carcinoma (OTSCC).

METHODS

Immunoexpression of PAI-1 was analyzed in 60 OTSCC specimens and classified as low-expression (≤50% of positive cells) or high-expression (>50%). In vitro effects of recombinant human PAI-1 (rhPAI-1) were assessed through functional assays on the OTSCC-derived cell line SCC-25. Three cell groups were evaluated: G0 (control), G10 (10 nM rhPAI-1), and G20 (20 nM rhPAI-1).

RESULTS

High membrane expression of PAI-1 was associated with tumor budding (p = 0.046) and high-risk cases (p = 0.043). Cytoplasmic and membrane expression of PAI-1 was not associated with patient survival. Cell viability (p = 0.020) and progression to the S-phase of the cell cycle (p = 0.024) were higher in G10 and G20 at 24 h. The percentages of apoptotic/necrotic cells were not affected by rhPAI-1. The presence of rhPAI-1 increased cell migration (p = 0.039) and invasion (p = 0.039) after 24 and 72 h, respectively.

CONCLUSION

Our findings indicate the involvement of PAI-1 in the biological behavior of OTSCC, although its expression may not predict patient survival. The in vitro results suggest that PAI-1 stimulates cell proliferation, migration and invasion and may contribute to the aggressive phenotype of OTSCC.

Comparison between computed tomography and ultrasound for presurgical evaluation of oral tongue squamous cell carcinoma tumor thickness

PURPOSE

To compare the accuracy of oral tongue squamous cell carcinoma (OTSCC) tumor thickness (TT) measured on CT to intraoperative ultrasound (US) and histopathology.

METHODS AND MATERIALS

Twenty-six patients with OTSCC who underwent tumor resection by a single surgeon with simultaneous intraoperative US between 3/2016 and 4/2019 were prospectively identified, and their data reviewed. TT was independently measured in 19 patients who underwent preoperative CT (cTT) by two neuroradiologists blinded to US and histological results. The confidence level of interpretation of cTT was recorded by each reader using a 5-point Likert scale. The degree of dental artifact on CT was also scored. cTT was compared to TT measured on intraoperative US (uTT) and histopathologic assessment of TT (hTT).

RESULTS

OTSCC was visualized on CT in 52% (10/19) and 63% (12/19) of cases for readers 1 and 2, respectively. Mean Likert score was 0.42 for reader 1 and 0.73 for reader 2. Mean cTT of OTSCCs was 5.8 mm +/- 1.7 mm (n = 11). In comparison, mean uTT and hTT were 7.6 mm±3.5 mm and 7.1 +/- 4.2 mm, respectively. The Pearson coefficient (95% confidence interval) was 0.10 (-0.53-0.66) between cTT and hTT (n = 11) and 0.93 (0.74-0.98) between uTT and hTT.

CONCLUSIONS

Preoperative CT is not reliable for assessment of TT in OTSCC compared to US and histopathology, particularly for OTSCC under 10 mm. US offers a practical complementary imaging tool with a unique role for primary tumor assessment that can aid in pre-operative planning, especially for small tumors.

The utility of intra-oral ultrasound in improving deep margin clearance of oral tongue cancer resections

OBJECTIVES

To investigate the potential utility of intra-oral ultrasound (IOUS) in guiding deep margin clearance and measuring depth of invasion (DOI) of oral tongue carcinomas (OTC).

MATERIALS AND METHODS

Retrospective chart review of consecutive patients with T1-T3 OTC who underwent intraoperative ultrasound-guided resection and a comparator group that had undergone resection without the use of IOUS both by a single surgeon. Data was extracted from operative, pathology and radiology reports. Deep margins and DOI were reviewed by a dedicated head and neck pathologist. Correlation between histologic and ultrasound DOI was assessed using Pearson correlation.

RESULTS

A total of 23 patients were included in the study cohort with a comparator group of 21 patients in the control group. None of the patients in the study cohort had a positive (cut-through) deep margin and the mean deep margin clearance was 8.5 ± 4.9 and 6.7 ± 3.8 for the IOUS and non-IOUS groups respectively (p-value 0.18) showing a non-significant improvement in the IOUS group. As a secondary outcome, there was a strong correlation between histologic and ultrasound DOI (0.9449).

CONCLUSION

Ultrasound appears to be a potentially effective tool in guiding OTC resections. In this small series, IOUS facilitated deep margin clearance and resulted in a non-statistically significant increase in deep margin clearance. Intraoral ultrasound can accurately measure lesional DOI.

Assessment of tumor depth in oral tongue squamous cell carcinoma with multiparametric MRI: correlation with pathology

OBJECTIVES

To compare the correlation of depth of invasion (DOI) measured on multiple magnetic resonance imaging (MRI) sequences and pathological DOI, in order to determine the optimal MRI sequence for measurement.

METHODS

A total of 122 oral tongue squamous cell carcinoma (OTSCC) patients were retrospectively analyzed, who had received preoperative MRI and surgical resection. DOIs measured on fat-suppressed T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), dynamic enhanced-T1 high-resolution insotropic volume examination (e-THRIVE), and contrast-enhanced fat-suppressed T1WI (CE-T1WI) were respectively compared to those measured in pathologic specimens. The cutoff value of the best correlated MRI sequence was determined, and the T staging accuracy of MRI-derived DOI was evaluated.

RESULTS

DOI derived from e-THRIVE showed the best correlation (r = 0.936, p < 0.001) with pathological DOI. The area under the curve values of MRI-derived DOI distinguishing T1 stage from T2 stage and distinguishing T2 stage from T3 stage were 0.969 and 0.974, respectively. The T staging criteria of MRI-derived DOI were 6.2 mm and 11.4 mm, with a staging accuracy of 86.9% compared to pathological DOI criteria of 5 mm and 10 mm.

CONCLUSION

E-THRIVE was the optimal MR sequence to measure the MR-derived DOI, and DOI derived from e-THRIVE could serve as a potential cut-off value as a clinical T staging indicator of OTSCC.

KEY POINTS

• Multiparametric MRI helps radiologists to assess the neoplasm invasion in patients with oral tongue squamous cell carcinoma. • Retrospective study indicated that measurement was most accurate on enhanced-T1 high-resolution insotropic volume examination dynamic contrast enhancement images. • T staging of oral tongue squamous cell carcinoma was accurate according to the dynamic contrast enhancement MRI-derived depth of invasion.

Correlation Of Preoperative Volume Of Oral Tongue Squamous Cell Carcinoma (SCC) On CT Scan With Postsurgical Tumour Size

BACKGROUND

Computed tomography (CT) radiological investigation is commonly used worldwide as a reliable method for determining the existence of oral tongue squamous cell carcinoma. This research was carried out to determine the correlation between the pre-surgical results of the CT scan and the size of the post-surgical tumour.

METHODS

An analytical crosssectional study was conducted at the radiology department of Jinnah Post Graduate Medical Centre (JPMC), Karachi, Pakistan from May to October 2020. All patients aged 18 years or above of either gender having malignant tumours of the tongue already proven on biopsy were consecutively enrolled. Pre-surgery CT scan images were performed. The preoperative volume on CT scan then correlated with the post-surgical tumour size findings. The tumour thickness level of anterio-posterior (AP), transverse dimension (TS) and craniocaudal (CC) on pre-surgery CT scan and post-surgery tumour size were the outcome variables.

RESULTS

Of 84 patients, the mean age of the patients was 48.38 ±11.40 years. There were 56 (66.7%) males and 28 (33.3%) females. A moderate positive correlation of AP tumour size on CT scan was observed with post-surgical AP tumour size (r=0.671, p-value <0.001). Similarly, a moderate positive correlation of TS tumour size was observed with post-operative TS tumour size (r=0.692, p-value <0.001). While, a strong positive correlation of CC tumour size was observed with post-operative surgical tumour size (r=0.787, p-value <0.001).

CONCLUSIONS

This study has reported a strong positive correlation of tumour thickness level on CT scan with post-surgical findings for determining the oral tongue squamous cell carcinoma.

The prognostic role of the pre-treatment neutrophil to lymphocyte ratio (NLR) and tumor depth of invasion (DOI) in early-stage squamous cell carcinomas of the oral tongue

The appropriate surgical management of early-stage oral tongue squamous cell carcinoma (OTSCC) remains a debated topic. The aim of this study is to investigate the role of the pre-treatment neutrophil to lymphocyte ratio (NLR) and tumor depth of invasion (DOI) in predicting the presence of occult neck metastases in early-stage OTSCC. A retrospective analysis of patients affected by early-stage (cT1-T2 cN0) OTSCC who were submitted to elective neck dissection (END) was performed. Tumors were classified retrospectively according to the 8th TNM classification, the DOI was assessed on the pre-operative magnetic resonance imaging, and the pre-treatment NLR was calculated for each patient. A logistic regression model to estimate the probability π (x) of cervical metastases by studying the NLR and DOI was carried out. Next, the correlation between the two variables, the NLR and DOI, was preliminarily studied. A cohort of 110 patients was analyzed (mean age, 62 years old; male to female ratio 1.2:1). The patients were staged as cT1 in 53 cases and cT2 in 57 cases. A DOI greater than 5.4 mm and a NLR greater than 2.93 are associated with an increased risk of presenting occult cervical metastases. Furthermore, the variables NLR and DOI are linearly associated with a positive correlation, proved by Spearman's rank correlation coefficient rho of 0.64, with a unitary increase in the DOI of 1 mm directly associated with an increase of 0.47 in the NLR. The DOI and NLR can be effectively used to predict the occurrence of occult neck metastasis and therefore to plan an END in early-stage OTSCC.

Tongue conservation treatment for oral tongue squamous cell carcinoma with induction chemotherapy, surgery, and risk-adapted adjuvant therapy: A phase II trial

BACKGROUND

To assess the feasibility of tongue conservation treatment with induction chemotherapy (ICT), tongue conservation surgery, and risk-adapted postoperative adjuvant therapy in oral tongue squamous cell carcinoma (OTSCC).

METHODS

Patients with newly diagnosed OTSCC cT2-4 N0-2 M0 were recruited. The ICT with a regimen of docetaxel, cisplatin, and oral tegafur/uracil (DCU) was administrated every 21 days. After the first cycle of ICT (DCU1), patients with a more than 30% decrease in the longest diameter of primary tumor underwent a second cycle of ICT (DCU2). Tongue conservation surgery was performed after ICT, and risk-adapted adjuvant therapy was organized based on pathological features.

RESULTS

From July 2011 to December 2015, a total of 23 patients were enrolled, 87% of whom were classified as stage III-IV. Clinical responders to DCU1 and DCU2 were determined in 90.5% (19/21) and 88.2% (15/17) of patients. Tongue conservation surgery was performed in 16 responders to ICT. Only one patient had a positive margin (6.3%), and a complete pathologic response was achieved in eight patients (50%). Only one patient developed local recurrence after a median follow-up of 58.6 months (range, 7.9-105.2). The 5-year overall survival (0% vs. 87.5%, P = 0.001) and disease-specific survival (0% vs. 93.3%, P = 0.000) were significantly different between the DCU1 nonresponders and responders.

CONCLUSION

Tongue conservation treatment with ICT, followed by conservation surgery and risk-adapted adjuvant therapy, is feasible for patients with OTSCC who are good responders to ICT. However, the outcomes of nonresponders are dismal. Further study in a larger patient population is warranted.

Histologic evaluation of host immune microenvironment and its prognostic significance in oral tongue squamous cell carcinoma: a comparative study on lymphocytic host response (LHR) and tumor infiltrating lymphocytes (TILs)

BACKGROUND

Host immune microenvironment is a key component of anti-tumoral immune response, influencing tumor progression, regression, and treatment responses. There is a need for simple and reliable histologic measurements of host immune response in routine histopathologic diagnosis.

METHODS

The prognostic value of lymphocytic host response (LHR), a qualitative histologic grading scheme, was compared to stromal/intratumoral TIL (sTIL/iTIL) percentage, a quantitative measurement in a retrospective study of 329 patients with oral tongue squamous cell carcinoma (OTSCC) of 4 cm or less in size.

RESULTS

High sTIL predicted improved distant recurrence free survival on univariate survival analysis and was an independent prognostic factor for better overall survival on multivariate analysis. LHR and iTIL were not associated with the risk of nodal metastasis or outcome.

CONCLUSIONS

sTIL appears to be a superior quantitative histologic measurement for the host immune microenvironment compared with the qualitative LHR grading scheme. sTIL is an independent prognostic factor for overall survival in OTSCC.

The effect of interleukin-17F on vasculogenic mimicry in oral tongue squamous cell carcinoma

Oral tongue squamous cell carcinoma (OTSCC) is one of the most common cancers worldwide and is characterized by early metastasis and poor prognosis. Recently, we reported that extracellular interleukin-17F (IL-17F) correlates with better disease-specific survival in OTSCC patients and has promising anticancer effects in vitro. Vasculogenic mimicry (VM) is the formation of an alternative vasculogenic system by aggressive tumor cells, which is implicated in treatment failure and poor survival of cancer patients. We sought to confirm the formation of VM in OTSCC and to investigate the effect of IL-17F on VM formation. Here, we showed that highly invasive OTSCC cells (HSC-3 and SAS) form tube-like VM on Matrigel similar to those formed by human umbilical vein endothelial cells. Interestingly, the less invasive cells (SCC-25) did not form any VM structures. Droplet-digital PCR, FACS, and immunofluorescence staining revealed the presence of CD31 mRNA and protein in OTSCC cells. Additionally, in a mouse orthotopic model, HSC-3 cells expressed VE-cadherin (CD144) but lacked Von Willebrand Factor. We identified different patterns of VM structures in patient samples and in an orthotopic OTSCC mouse model. Similar to the effect produced by the antiangiogenic drug sorafenib, IL-17F inhibited the formation of VM structures in vitro by HSC-3 and reduced almost all VM-related parameters. In conclusion, our findings indicate the presence of VM in OTSCC and the antitumorigenic effect of IL-17F through its effect on the VM. Therefore, targeting IL-17F or its regulatory pathways may lead to promising therapeutic strategies in patients with OTSCC.

The prognostic role of histologic grade, worst pattern of invasion, and tumor budding in early oral tongue squamous cell carcinoma: a comparative study

Major pathology guidelines often mandate stating the histologic grade as a component of the pathology report for various types of cancer. However, the prognostic value of histologic grade in head and neck squamous cell carcinoma (HNSCC) is controversial at best, and there is a need for more reliable prognostic histologic factors to better stratify and manage patients with HNSCC. In this study, we compared three relevant histopathologic features (histologic grade, worst pattern of invasion (WPOI), and tumor budding) in a large single-center retrospective cohort of early oral tongue squamous cell carcinoma (OTSCC) with tumor greatest dimension ≤ 4 cm. Only histologic grade predicted distant metastasis free survival (DMFS) on univariate analysis. Tumor budding was associated with nodal metastasis, overall survival (OS), regional recurrence-free survival (RRFS), and DMFS and was a significant predictor for nodal metastasis on the multivariable logistic regression model. WPOI 5 was associated with high frequency of nodal metastasis and shortened OS and was an independent adverse prognostic factor for OS on multivariate analysis using the Cox proportional hazards model. WPOI and tumor budding were prognostically more relevant than histologic grade. Consideration should be given to include WPOI and tumor budding in the pathology reporting of OTSCC.

Effect of Sex Steroid Hormones on Tongue Cancer Cells In Vitro

BACKGROUND

Tongue cancer is more common in men than in women. Yet the effects of sex steroid hormones on the behaviour of oral tongue squamous cell carcinoma (OTSCC) are not well known. Matrix metalloproteinase 8 (MMP8) is expressed in OTSCC and can degrade estrogen receptors (ERs).

MATERIALS AND METHODS

Western blot was used to examine the levels of ERβ in OTSCC cell lines (HSC-3 and SCC-25). We evaluated the effects of estradiol and dihydrotestosterone (DHT) on HSC-3 and SCC-25 cell migration, invasion and viability. The effect of estradiol on the invasion of MMP8-overexpressing (MMP8⁺) and empty vector HSC-3 cells was examined using 3D spheroid invasion assay.

RESULTS

Both HSC-3 and SCC-25 cells expressed ERβ. In scratch assay, estradiol, but not DHT, reduced the migration and invasion of HSC-3 and SCC-25 cells. MMP8⁺ HSC-3 cells showed weaker invasion than empty vector cells, in line with previous reports. However, MMP8 overexpression did not alter the effect of estradiol on HSC-3 cell invasion in spheroid assay.

CONCLUSION

Estradiol inhibited the migration and invasion of OTSCC cells, whereas DHT had no effect. Our data suggest that MMP8 does not modulate the effect of estradiol in OTSCC cells. However, the sex difference in OTSCC incidence might partly be due to protective actions of estradiol in epithelial cell carcinogenesis.

Evaluation Challenges in the Validation of B7-H3 as Oral Tongue Cancer Prognosticator

B7-H3 was the only molecule identified with prognostic potential from a recent systematic review of the prognostic value of immune checkpoints in oral cancer. We aimed to validate this finding in a multicenter international cohort. We retrospectively retrieved 323 oral tongue squamous cell carcinoma (OTSCC) samples from three different countries (Brazil, Finland, and Norway) for immunostaining and scoring for B7-H3. We evaluated tumor immunogenicity by analyzing the amount of tumor-infiltrating lymphocytes and divided the tumors into immune hot and cold. To increase the reliability of the results, both digital and manual visual scoring were used. Survival curves were constructed based on the Kaplan-Meier method, and the Cox proportional hazard model was utilized for univariate and multivariate survival analysis. B7-H3 expression was not significantly associated with overall or disease-specific survival in the whole OTSCC cohort. When divided into immune hot and cold tumors, high B7-H3 expression was significantly associated with poor disease-specific and overall survival in the immune hot group, depending on the scoring method and the country of the cohort. This was achieved only in the univariate analysis. In conclusion, B7-H3 was a negative prognosticator for OTSCC patient survival in the subgroup of immune hot tumors, and was not validated as a prognosticator in the full cohort. Our findings suggest that the immune activity of the tumor should be considered when testing immune checkpoints as biomarkers.

TIPE2 suppresses progression and tumorigenesis of the oral tongue squamous cell carcinoma by regulating FoxP3+ regulatory T cells

To discover the effect of tumor necrosis factor-alpha-induced protein 8-like 2 (TIPE2) on the oral tongue squamous cell carcinoma (OTSCC) via affecting FoxP3⁺ regulatory T (Treg) cells. Immunohistochemistry was conducted to examine TIPE2 and FoxP3 expressions in OTSCC tumor tissues and corresponding oral mucosa. Tca8113 cells were transfected with TIPE2/control lentiviral activation particles followed by the detection with qRT-PCR, Western blotting, MTT assay, Wound healing, Transwell assay and Annexin V-FITC/PI staining. In vivo experiment was carried out on the nude mice xenografts of OTSCC with TIPE2 overexpression to observe the tumor volume and survival, and the CD4⁺ T cell subgroups were detected by flow cytometry. TIPE2 was lower in the OTSCC tissues than the corresponding oral mucosa, which was correlated with T stage, N stage, TNM stage, and differentiation of patients. Patients with TIPE2-positive expression had worse prognosis and lower expression of FoxP3⁺ Treg cells than the negative ones. Furthermore, TIPE2 overexpression curbed proliferation, invasion and migration of Tca8113 cells, while cell apoptosis was increased. Besides, TIPE2 suppressed the tumor growth and extended the survival of OTSCC mice, with the decreased proportion of FoxP3⁺ Treg cells in the spleen and tumor-infiltrated lymphocytes (TILs). The clinical results showed the down-regulation of TIPE2 in OTSCC tissues. Meanwhile TIPE2 overexpression affected OTSCC cells biological behavior in vitro, as well as exhibited strong tumor-growth suppressive effects in vivo, which may be a potential therapeutic target in OTSCC via regulating FoxP3⁺ Treg cells.

Limonin suppresses the progression of oral tongue squamous cell carcinoma via inhibiting YAP transcriptional regulatory activity

The suppressive roles of limonin have been established in various tumors. However, its roles in oral tongue squamous cell carcinoma (OTSCC) progression are still confusing. This work aims to explore limonin-mediated effects on OTSCC progression. CCK8 analysis was performed to evaluate limonin-mediated effects on OTSCC cell viability. Wound healing and transwell invasion analysis were constructed to examine the effects of limonin on OTSCC cell migration and invasion capacity. RT-qPCR, western blot and luciferase reporter assays were used to explore the underlying mechanisms contributing to limonin-mediated effects on OTSCC progression. It was found that limonin significantly suppressed the viability of OTSCC cells. Additionally, limonin reduced the migration and invasion ability of OTSCC cells. Mechanistically, limonin suppresses OTSCC progression by promoting the nuclear to cytoplasm translocation of YAP, decreasing YAP protein expression and subsequently decreasing YAP transcriptional regulatory activity, this is responsible for limonin-mediated suppression on OTSCC progression. Thus, this work suggests that limonin suppresses OTSCC progression through inhibiting YAP transcriptional regulatory activity.

Pre-treatment Neutrophil-to-Lymphocyte Ratio as a predictor for occult cervical metastasis in early stage (T1-T2 cN0) squamous cell carcinoma of the oral tongue

BACKGROUND

Optimum management of clinically negative neck (cN0) remains controversial in early stage (T1-T2) squamous cell cancer of the oral tongue (OTSCC). The purpose of this study was to investigate the value of pre-treatment Neutrophil-to lymphocyte ratio (NLR) in predicting occult cervical metastasis in stage I and II OTSCC.

METHODS

We carried out a retrospective chart review on 110 patients suffering from early stage OTSCC who were surgically treated with tumour excision and elective neck dissection (END). Our cohort was divided in pN+ and pN0 groups basing on histopathological examination after elective neck dissection. For each patient pre-treatment NLR was calculated.

RESULTS

A statistically significant relationship between high levels of pre-treatment NLR and probability rate for neck occult metastases (0.000496 p-value) has been found. On our model the cut-off value was set for NLR >2.93. Above this level the probability to finding metastasis in a clinically negative neck increases exponentially.

CONCLUSION

These preliminary results offer clinicians an easily obtainable tool to stratify patients based on risks of metastatic node in whom END could be indicated.

Patients with unilateral squamous cell carcinoma of the tongue and ipsilateral lymph node metastasis do not profit from bilateral neck dissection

OBJECTIVES

The purpose of this study was to evaluate the necessity of elective bilateral neck dissection for treating strict unilateral squamous cell carcinoma (SCC) of the tongue.

METHODS

A cohort of 169 patients with unilateral non-midline crossing SCCs of the tongue treated by local resection and neck dissection was investigated. Study endpoints were nodal relapse and overall survival. The mean follow-up was 7.4 years.

RESULTS

A total of 146 (88.1%) patients were treated by neck dissection. Lymph node metastases were diagnosed in 50 (34.2%) patients. Only two (1.1%) had contralateral lymph node metastases. Risk factors for developing a primary lymph node metastasis were size of tumor (T2/T3, p = 0.03; OR = 2.2), lymphangiosis (p = 0.003; OR = 4.7), and higher-grade differentiation (p = 0.051; OR = 2.43). Metachronous lymph node metastases were detected in 23 (13.6%) patients (19 ipsilateral, one contralateral and three bilateral). The main risk factor for developing a metachronous lymph node metastasis was the presence of a primary lymph node metastasis (p = 0.004; HR = 4.65). Patients with initial neck dissection came up with lower 5-year recurrence rates (13.6%) compared to patients without neck dissection (27.3%; p = 0.014). Bilateral neck dissection showed no advantage regarding nodal relapse free and overall survival (p = 0.606) compared to unilateral neck dissection irrespective of initial N or T stage.

CONCLUSION

Patients with unilateral SCC of the tongue benefit from an ipsilateral neck dissection regarding nodal relapse. The value of elective bilateral neck dissection as standard treatment seems questionable even if positive lymph nodes were diagnosed ipsilateral at primary therapy.

Prognostic impact of perineural invasion in early stage oral tongue squamous cell carcinoma: Results from a prospective randomized trial

BACKGROUND

Although perineural invasion (PNI) has been recognized as a poor prognostic factor for oral cancer, few studies have focused on tongue squamous cell carcinoma (TSCC). Using a prospective randomized trial, this study investigated the role of PNI in the regional control and survival of the patients with cT1-2N0 TSCC, and clarified the benefit of neck management based on PNI status.

METHODS

PNI status was reviewed under H&E staining in tumors of 221 patients with cT1-2N0 TSCC, who were randomly assigned into elective neck dissection (END) group (n = 111) and observation group (n = 110). Oncologic and survival outcomes were analyzed by multivariate regression and Kaplan-Meier analyses.

RESULTS

PNI was identified in 34 patients and multivariate analyses revealed that PNI remained an independent predictor for cervical lymph node metastasis (CLNM), local relapse, neck relapse and disease-specific survival (DSS) after controlling for T stage and pathologic differentiation. END could not improve the benefit for patients. Stratified analysis revealed that END also could not improve neck control or DSS among patients with PNI.

CONCLUSIONS

This study demonstrated that PNI was an invaluable pathological parameter to independently predict cervical metastasis, local relapse, neck relapse and poor survival outcomes, but END could not improve benefits compared to observation for the PNI-positive patients.

A 16-gene signature predicting prognosis of patients with oral tongue squamous cell carcinoma

Background

Oral tongue squamous cell carcinoma (OTSCC) is the most common subtype of oral cancer. A predictive gene signature is necessary for prognosis of OTSCC.

Methods

Five microarray data sets of OTSCC from the Gene Expression Omnibus (GEO) and one data set from The Cancer Genome Atlas (TCGA) were obtained. Differentially expressed genes (DEGs) of GEO data sets were identified by integrated analysis. The DEGs associated with prognosis were screened in the TCGA data set by univariate survival analysis to obtain a gene signature. A risk score was calculated as the summation of weighted expression levels with coefficients by Cox analysis. The signature was used to distinguish carcinoma, estimated by receiver operator characteristic curves and the area under the curve (AUC). All were validated in the GEO and TCGA data sets.

Results

Integrated analysis of GEO data sets revealed 300 DEGs. A 16-gene signature and a risk score were developed after survival analysis. The risk score was effective to stratify patients into high-risk and low-risk groups in the TCGA data set (P < 0.001). The 16-gene signature was valid to distinguish the carcinoma from normal samples (AUC 0.872, P < 0.001).

Discussion

We identified a useful 16-gene signature for prognosis of OTSCC patients, which could be applied to clinical practice. Further studies were needed to prove the findings.

Prognostic value of volumetric FDG PET/CT parameters in patients with oral tongue squamous cell carcinoma who were treated by superselective intra-arterial chemoradiotherapy

PURPOSE

This study aimed to evaluate the predictive and prognostic value of FDG PET/CT-based volumetric parameters in patients with oral tongue squamous cell carcinoma (OTSCC) treated by superselective intra-arterial chemoradiotherapy (IA-CRT).

METHODS

We conducted a retrospective study including 33 patients with biopsy-proven OTSCC between May 2007 and February 2016. All of the patients were treated by IA-CRT. Pretreatment SUV_max and metabolic tumor volume (MTV) of the primary tumor were measured. The SUV thresholds of 2.5 and 5.0 were used. Progression-free survival (PFS) and overall survival (OS) were chosen as endpoints to evaluate prognosis. Univariate and multivariate analyses were performed to assess the potential independent effect of FDG PET/CT parameters.

RESULTS

The median follow-up for surviving patients was 40.7 months (range 6.0-107.5 months). In univariate and multivariate analyses, SUV_max and MTV (5.0) were independent prognostic factors for PFS. In univariate analysis, SUV_max failed to predict OS. MTV (5.0) was a significant prognostic factor for OS, but multivariate analysis failed to show statistical independence because it could not exclude the possibility of an artifact due to N stage.

CONCLUSIONS

FDG PET/CT-based volumetric parameters may be significant prognostic markers for survival of patients with OTSCC who are treated by IA-CRT.

Histamine H4 receptor signalling in tongue cancer and its potential role in oral carcinogenesis - a short report

PURPOSE

Recent reports indicate that histamine and its novel, high-affinity histamine H₄ receptor (H₄R) play a role in carcinogenesis, and thus H₄R signalling has become a focus of increasing interest in the pathogenesis of many cancers. The roles of H₄R in oral epithelial dysplasia (OED) and oral tongue squamous cell carcinoma (OTSCC) are unknown. The purpose of this study was to assess H₄R expression in OTSCC patients and in OTSCC-derived cell lines.

METHODS

Biopsies taken from OED, OTSCC and healthy oral mucosa were studied by immunostaining. Primary human oral keratinocytes (HOKs) and two OTSCC-derived cell lines (HSC-3 and SCC-25) were used for the in vitro studies. Quantitative real-time PCR was used to measure oncogene expression in the stimulated HOKs.

RESULTS

We found that H₄R-immunoreactivity was significantly reduced in the OED and OTSCC samples, especially in the samples with higher histopathological grades and noticeably increased mast cell counts. The presence of H₄R in HSC-3 cells had clearly waned, in contrast to the HOKs. Gene expression data indicated that histamine-relevant inflammatory and environmental elements may participate in the regulation of oncogenes.

CONCLUSIONS

Our results suggest an association between H₄R and oral carcinogenesis. Furthermore, our findings raise a potential implication of histamine-mediated factors in the regulation of oncogenes, possibly via mast cells, as crucial components of the tumor microenvironment. The identification of new elements that govern oral cancer development is highly relevant for the development of novel therapeutic approaches in OTSCC.

The maximum standardized uptake value increment calculated by dual-time-point 18F-fluorodeoxyglucose positron emission tomography predicts survival in patients with oral tongue squamous cell carcinoma

The aim of this study was to investigate the prognostic value of dual-time-point (DTP) ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) imaging in primary oral tongue squamous cell carcinoma (OTSCC). The study included 52 patients who underwent preoperative ¹⁸F-FDG PET scans at two time points, namely 1 h and 2 h after injection. The following PET parameters were calculated: maximum standardized uptake value (SUVmax) for both time points (SUV early, SUV delayed); retention index (RI); and SUVmax increment (ΔSUVmax). Receiver operating characteristic (ROC) curve analysis was performed to define the optimal cutoff point for these parameters. Overall survival was calculated using the Kaplan–Meier method. Prognostic factors for patients with OTSCC were evaluated using the univariate log-rank test and a multivariate Cox proportional hazards model. ROC analysis revealed that the area under the curve was higher and more accurate for ΔSUVmax than for the other parameters. Additionally, patients with a ΔSUVmax ≥0.9 had significantly worse survival outcomes (28.9% vs 92.6%; p < 0.01). Univariate analysis showed that prognosis was significantly correlated with clinical T stage, local recurrence, perineural invasion, vascular invasion, and PET parameters (p < 0.05 for all). Multivariate analysis showed that local recurrence (hazard ratio = 3.60; p = 0.02) and ΔSUVmax (hazard ratio = 8.43; p < 0.01) were independent prognostic factors. ΔSUVmax determined using DTP ¹⁸F-FDG PET may be an additional prognostic factor in OTSCC patients.

Establishment and characterization of an oral tongue squamous cell carcinoma cell line from a never-smoking patient

OBJECTIVE

The rising incidence of oral tongue squamous cell carcinoma (OTSCC) in patients who have never smoked and the paucity of knowledge of its biological behavior prompted us to develop a new cell line originating from a never-smoker.

MATERIALS AND METHODS

Fresh tumor tissue of keratinizing OTSCC was collected from a 44-year-old woman who had never smoked. Serum-free media with a low calcium concentration were used in cell culture, and a multifaceted approach was taken to verify and characterize the cell line, designated UCSF-OT-1109.

RESULTS

UCSF-OT-1109 was authenticated by STR DNA fingerprint analysis, presence of an epithelial marker EpCAM, absence of human papilloma virus (HPV) DNA, and SCC-specific microscopic appearance. Sphere-forming assays supported its tumorigenic potential. Spectral karyotype (SKY) analysis revealed numerical and structural chromosomal abnormalities. Whole-exome sequencing (WES) identified 46 non-synonymous and 13 synonymous somatic single-nucleotide polymorphisms (SNPs) and one frameshift deletion in the coding regions. Specifically, mutations of CDKN2A, TP53, SPTBN5, NOTCH2, and FAM136A were found in the databases. Copy number aberration (CNA) analysis revealed that the cell line loses chromosome 3p and 9p, but lacks amplification of 3q and 11q (as does HPV-negative, smoking-unrelated OTSCC). It also exhibits four distinctive focal amplifications in chromosome 19p, containing 131 genes without SNPs. Particularly, 52 genes showed >3- to 4-fold amplification and could be potential oncogenic drivers.

CONCLUSION

We have successfully established a novel OTSCC cell line from a never-smoking patient. UCSF-OT-1109 is potentially a robust experimental model of OTSCC in never-smokers.

Elective neck dissection in unilateral carcinomas of the tongue: Unilateral versus bilateral approach

PURPOSE

Elective neck dissection (END) is a common primary treatment strategy for oral tongue squamous cell carcinoma (OTSCC), although uncertainty remains regarding the necessary extent of END for strictly unilateral early stage OTSCC. The authors evaluated two END variations, unilateral and bilateral, to determine the optimal extent.

MATERIALS AND METHODS

A retrospective cohort study was performed on patient data from two departments of oral and maxillofacial surgery. All previously untreated patients from both clinics who were diagnosed with early-stage (pT1-2) unilateral OTSCC were included. The following variables were collected: age, gender, END type/extent, tumor localization, later nodal metastasis, and TNM status. Statistical analyses were performed (p < 0.05).

RESULTS

A total of 150 patients were identified, 105 receiving unilateral END and 45 bilateral END. The rates of postoperative positive lymph nodes were 21.9% for ipsilateral END and 26.7% for bilateral END (bilateral END: all positive nodes ipsilateral). In all, 14 patients in the ipsilateral group developed nodal metastasis during tumor aftercare (11 patients ipsilateral, 3 patients contralateral neck). In the bilateral group, nodal metastasis was later observed in 4 cases (8.9%; 3 cases ipsilateral, 1 case contralateral neck). Statistical analysis could not detect significant differences between the END procedures.

CONCLUSION

As both procedures lead to similar results in preventing or omitting possible later nodal metastasis, the two methods seem to be valuable alternatives. In conclusion, we recommend bilateral END because of advantages with regard to oncologic safety and esthetic outcome, but the decision for END should always be according to the patient's general health status, comorbidities, and individual tumor risk profile.

Patterns of cancer cell sphere formation in primary cultures of human oral tongue squamous cell carcinoma and neck nodes

Recently a sub-population of cells with stem cell characteristics, reported to be associated with initiation, growth, spread and recurrence, has been identified in several solid tumors including oral tongue squamous cell carcinoma (OTSCC). The aim of our pilot study was to isolate CD44+ cancer stem cells from primary cultures of OTSCC and neck node Level I (node-I) biopsies, grow cell spheres and observe their characteristics in primary cultures. Parallel cultures of hyperplastic lesions of tongue (non-cancer) were set up as a control. Immunohistochemistry was used to detect CD44/CD24 expression and magnetic activated cell sorting to isolate CD44+ cell populations followed by primary cell culturing. Both OTSCC and node-I biopsies produced floating spheres in suspension, however those grown in hyperplastic and node-I primary cultures did not exhibit self-renewal properties. Lymph node metastatic OTSCC, express higher CD44/CD24 levels, produce cancer cell spheres in larger number and rapidly (24 hours) compared to node negative OTSCC (1 week) and non-cancer specimens (3 weeks). In addition, metastatic OTSCC have the capacity for proliferation for up to three generations in primary culture. This in vitro system will be used to study cancer stem cell behavior, therapeutic drug screening and optimization of radiation dose for elimination of resistant cancer cells.

Prognostic value of volume-based (18)F-fluorodeoxyglucose PET/CT parameters in patients with clinically node-negative oral tongue squamous cell carcinoma

Objective

To evaluate the prognostic value of volume-based metabolic parameters measured with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) in patients with clinically node-negative (cN0) oral tongue squamous cell carcinoma (OTSCC) as compared with other prognostic factors.

Materials and Methods

In this study, we included a total of 57 patients who had been diagnosed with cN0 tongue cancer by radiologic, ¹⁸F-FDG PET/CT, and physical examinations. The maximum standardized uptake value (SUV_max), average SUV (SUV_avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for primary tumors were measured with ¹⁸F-FDG PET. The prognostic significances of these parameters and other clinical variables were assessed by Cox proportional hazards regression analysis.

Results

In the univariate analysis, pathological node (pN) stage, American Joint Committee on Cancer (AJCC) stage, SUV_max, SUV_avg, MTV, and TLG were significant predictors for survival. On a multivariate analysis, pN stage (hazard ratio = 10.555, p = 0.049), AJCC stage (hazard ratio = 13.220, p = 0.045), and MTV (hazard ratio = 2.698, p = 0.033) were significant prognostic factors in cN0 OTSCC patients. The patients with MTV ≥ 7.78 cm³ showed a worse prognosis than those with MTV < 7.78 cm³ (p = 0.037).

Conclusion

The MTV of primary tumor as a volumetric parameter of ¹⁸F-FDG PET, in addition to pN stage and AJCC stage, is an independent prognostic factor for survival in cN0 OTSCC.