Tissue microarray use for immunohistochemical study of ameloblastoma

Machine learning-based radiomics for predicting BRAF-V600E mutations in ameloblastoma

Background

Ameloblastoma is a locally invasive and aggressive epithelial odontogenic neoplasm. The BRAF-V600E gene mutation is a prevalent genetic alteration found in this tumor and is considered to have a crucial role in its pathogenesis. The objective of this study is to develop and validate a radiomics-based machine learning method for the identification of BRAF-V600E gene mutations in ameloblastoma patients.

Methods

In this retrospective study, data from 103 patients diagnosed with ameloblastoma who underwent BRAF-V600E mutation testing were collected. Of these patients, 72 were included in the training cohort, while 31 were included in the validation cohort. To address class imbalance, synthetic minority over-sampling technique (SMOTE) is applied in our study. Radiomics features were extracted from preprocessed CT images, and the most relevant features, including both radiomics and clinical data, were selected for analysis. Machine learning methods were utilized to construct models. The performance of these models in distinguishing between patients with and without BRAF-V600E gene mutations was evaluated using the receiver operating characteristic (ROC) curve.

Results

When the analysis was based on radiomics signature, Random Forest performed better than the others, with the area under the ROC curve (AUC) of 0.87 (95%CI, 0.68-1.00). The performance of XGBoost model is slightly lower than that of Random Forest, and its AUC is 0.83 (95% CI, 0.60-1.00). The nomogram evident that among younger women, the affected region primarily lies within the mandible, and patients with larger tumor diameters exhibit a heightened risk. Additionally, patients with higher radiomics signature scores are more susceptible to the BRAF-V600E gene mutations.

Conclusions

Our study presents a comprehensive radiomics-based machine learning model using five different methods to accurately detect BRAF-V600E gene mutations in patients diagnosed with ameloblastoma. The Random Forest model's high predictive performance, with AUC of 0.87, demonstrates its potential for facilitating a convenient and cost-effective way of identifying patients with the mutation without the need for invasive tumor sampling for molecular testing. This non-invasive approach has the potential to guide preoperative or postoperative drug treatment for affected individuals, thereby improving outcomes.

HIF-1α Is Associated with Resistance to Hypoxia-Induced Apoptosis in Ameloblastoma

Background

Ameloblastoma (AMB) is a benign odontogenic tumour, with an aggressive local behaviour and a high rate of recurrence. Previous studies have demonstrated that hypoxia-induced factor alpha 1 (HIF-1α) and activated caspase-3 contribute to tumour invasiveness and cytogenesis in ameloblastoma. Hypoxia increases HIF-1α levels, which triggers a number of signalling pathways. This paper aimed to present data in the study of hypoxia-activated signalling pathways that modulate proapoptotic and antiapoptotic events in AMB.

Methods

Twenty cases of AMB and ten cases of dental follicle (DF) were used to analyse the immunoexpression of HIF-1α, p53, BNIP3, Bcl-2, IAP-2, GLUT1, and Bax. To contribute to the study, an analysis of expression and genetic interaction was performed using the cell line AME-1.

Results

AMB and DF expressed the studied proteins. These proteins showed significantly greater immunoexpression in AMB compared with the DF (p < 0.05). HIF-1α showed an important association with GLUT1, and a positive correlation was observed among p53, Bcl-2, and IAP-2. Transcriptomic analysis showed the significant expression of the studied proteins, and the network generated showed a direct association of HIF-1αF with GLUT1 (SLC2A1), TP53, and LDHA. Interestingly, GLUT1 also exhibited direct interaction with TP53 and LDHA.

Conclusion

In AMB tumorigenesis, hypoxia is possibly related to antiapoptotic events, which suggests an important role for HIF-1α, GLUT1, Bcl-2, IAP-2, and possibly p53.

A Novel lncRNA ENST00000512916 Facilitates Cell Proliferation, Migration and Cell Cycle Progression in Ameloblastoma

Objective

Our purpose was to identify up-regulated long noncoding RNA ENST00000512916 in ameloblastoma (AB) and explore its role in the progression of AB.

Methods

We analyzed lncRNA microarray expression profile between six paired AB and normal oral mucosa (NOM) tissues. An up-regulated lncRNA, ENST00000512916 was identified and validated by real-time qPCR. Cell proliferation, migration and cell cycle were detected by CCK-8 assay, transwell chamber and flow cytometry, respectively. Western blotting analysis was used to measure the expression of cell-cycle-related proteins including CyclinD1 and Cyclin-dependent kinase (CDK) 2/4/6. In addition, Xenograft tumor model was constructed to investigate tumor growth.

Results

Real-time qPCR confirmed that lncRNA ENST00000512916 was up-regulated in AB tissues. ENST00000512916 knockdown significantly inhibited cell proliferation, migration and the expression of CDK2/4/6 in AM-1 cells. Moreover, ENST00000512916 knockdown suppressed tumor growth in vivo. We also found that ENST00000512916 overexpression significantly promoted the expression of HOXC13 in AM-1 cells. Overexpression of ENST00000512916 promoted cell cycle progression in AM-1 cells, which was reversed by HOXC13 knockdown.

Conclusion

Our findings reveal that lncRNA ENST00000512916 promotes cell proliferation, migration and cell cycle progression of AB.

COX-2 as a determinant of lower disease-free survival for patients affected by ameloblastoma

Ameloblastoma is a locally aggressive neoplasm with a poorly understood pathogenesis. Therefore, the aim of this study is to investigate whether COX-2 expression is associated with ameloblastoma microvascular density (MVD) and with tumor aggressiveness. Sixty-three cases of primary ameloblastomas arranged in tissue microarray were submitted to immunohistochemistry against cyclooxigenase-2 (COX-2) and CD34. Clinicopathological parameters regarding sex, age, tumour size, tumour duration, tumour location, treatment, recurrences, radiographic features, vestibular/lingual and basal cortical disruption and follow-up data were obtained from patients' medical records and correlated with the proteins expression. The results on BRAF-V600E expression were obtained from our previous study and correlated with COX-2 and CD34 expressions. Log-rank univariate analysis and multivariate Cox regression model were done to investigate the prognostic potential of the molecular markers. Twenty-eight cases (44.4%) exhibited cytoplasmic positivity for COX-2, predominantly in the columnar peripheral cells, with a mean MVD of 2.2 vessels/mm². COX-2 was significantly associated with recurrences (p < 0.001) and BRAF-V600E expression (p < 0.001), whereas lower MVD was associated with the use of conservative therapy (p = 0.004). Using univariate and multivariate analyses, COX-2 was significantly associated with a lower 5-year disease-free survival (DFS) rate (p < 0.001 and p = 0.012, respectively), but not with a higher MVD (p = 0.68). In conclusion, COX-2 expression in ameloblastomas is not associated with MVD, but it is significantly associated with recurrences and with a lower DFS.

Prognostic importance of FGF2 and FGFR1 expression for patients affected by ameloblastoma

BACKGROUND

Fibroblast growth factor 2 (FGF2) and FGF receptor 1 (FGFR1) have been investigated in different human neoplasms and were shown to play important roles in the pathogenesis of these diseases; however, very few are known regarding their prognostic importance in the context of ameloblastoma. Therefore, the aim of this study was to investigate whether the expression of FGF2 and FGFR1 is associated with ameloblastoma clinical behavior.

METHODS

Fifty-eight cases of ameloblastoma arranged in tissue microarray were submitted to immunohistochemistry against FGF2 and FGFR1. Clinicopathological parameters regarding sex, age, tumor size, duration and location, treatment, recurrences, radiographic features, cortical disruptions, and follow-up data were obtained from patients' medical records and correlated with the molecules expression. Univariate and multivariate Cox regression analyses were used to investigate the prognostic potential of the biomarkers.

RESULTS

Forty-four cases (75.9%) exhibited cytoplasmic positivity for FGF2 in central and peripheral epithelial cells, 46 of 58 (79.3%) showed FGFR1 cytoplasmic positivity predominantly in the columnar peripheral cells, and 43 cases (74.1%) were positive for both. Expression of FGF2 and FGF2 + FGFR1 was associated with tumor recurrences (P = .05). However, univariate and multivariate analyses did not demonstrate a significant influence of FGF2, FGFR1, or FGF2 + FGFR1 in the 5-year disease-free survival (DFS) rate (P = .27, P = .33, and P = .25, respectively).

CONCLUSION

Cytoplasmic expression of FGF2 and FGF2 + FGFR1 is associated with ameloblastoma recurrence, but FGF2 and FGFR1 are not determinants of a lower DFS.

Tissue microarray is suitable for scientific biomarkers studies in endometrial cancer

The aim of this study was to define the concordance between tissue microarrays (TMAs) of different sizes and whole slide for 15 different antibodies in endometrial cancer and study the use of TMAs in preoperative endometrial samples. Cores of preoperative and hysterectomy specimens of 14 endometrial cancer and three atypical hyperplasia cases were collected in TMA blocks. Two 0.6-mm and two 2.0-mm cores were used from each sample. Different antibodies were tested in TMAs and compared with results of whole slides of hysterectomy. Tested antibodies were as follows: ER, PR, p53, Ki-67, MLH1, PMS2, MSH2, MSH6, ARID1A, stathmin, IMP3, L1CAM, PTEN, β-catenin, and p16. Seventeen cases with four cores per paraffin block (both 0.6 and 2.0 mm in duplicate) and 15 different antibodies resulted in a total of 1020 cores for both preoperative and hysterectomy specimen. Overall, 2.0-mm cores were more assessable for evaluation than 0.6-mm cores (96.0 versus 79.5%, p < 0.01). For most antibodies, a substantial to good agreement between hysterectomy TMA and whole slide was present, with lowest agreement for p16 and stathmin and perfect agreement for mismatch repair proteins. Preoperative TMAs showed for most antibodies moderate to perfect agreement with hysterectomy TMAs. In conclusion, 2.0-mm cores are the preferred size for immunohistochemical studies in endometrial cancer. For all tested antibodies, TMAs are a good alternative for whole slide analysis in scientific studies with large patient cohorts, even in preoperative endometrial samples. However, caution is required for interpretation of TMA results of p16 and stathmin.

BRAF-V600E expression correlates with ameloblastoma aggressiveness

AIMS

The aim of this study was to investigate whether the expression of BRAF-V600E determines an aggressive clinical and molecular presentation of ameloblastoma.

METHODS AND RESULTS

Ninety-three cases of solid ameloblastomas were arranged in a 1.0-mm tissue microarray (TMA) block. Immunohistochemistry against a large panel of cytokeratins (CK), epidermal growth factor receptor (EGFR), parathyroid hormone-related peptide (PTHrP), syndecan-1, Ki67, p53 and BRAF-V600E were performed. Clinicopathological parameters, including sex, age, tumour size, tumour duration, tumour location, treatment, recurrences, radiographic pattern, vestibular/lingual and basal cortical plates disruption and follow-up data, were obtained from patients' medical records. Immunoexpression of BRAF-V600E was investigated in 73 cases that remained available in TMA sections. Our results indicated that 46.6% (34 cases) demonstrated cytoplasm positivity (six weak and 28 strong positivity). BRAF-V600E expression was associated significantly with the expression of CK8 (P = 0.00077), CK16 (P = 0.05), PTHrP (P = 0.0082) and p53 (P = 0.0087). Additionally, a significant association was seen with the presence of recurrences (P = 0.0008), multilocular radiographic appearance (P = 0.044) and disruption of basal bone cortical (P = 0.05). Univariate analysis showed that BRAF-positive cases (P = 0.001), EGFR-negative/weak positive cases (P = 0.03) and multilocular tumours (P = 0.04) had a significantly lower disease-free survival rate, but these parameters were not considered independent prognostic factors in the multivariate analysis (P > 0.05).

CONCLUSIONS

Our findings suggest an association of BRAF-V600E with parameters of a more aggressive behaviour of ameloblastoma, supporting the future use of BRAF inhibitors for targeted therapy of this neoplasm.