Histological implications of high-power laser use in the oral soft tissue lesions: a systematic review.

The objective of this study was to describe the histological artifacts caused by high-power laser use compared to cold scalpel surgery in oral soft tissue lesions. Clinical studies that evaluated and compared histological artifacts resulting from the use of high-power lasers and cold scalpels in oral soft tissue lesions biopsies were retrieved from seven databases and four grey literatures, up to July 2022. The risk of bias was investigated using the ROBINS-I tool. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Seven studies were eligible for qualitative analysis. Based on the results obtained, those four studies had a low risk of bias, and three studies had an unclear risk of bias. The certainty of the evidence was classified as low. Limited evidence showed that epithelial artifacts such as loss of intraepithelial and subepithelial adhesions, accompanied by pyknotic, fusiform, and/or hyperchromic nuclei, were more common when a high-power laser device was used. Four articles reported that the use of high-power lasers did not interfere with the histopathological diagnosis of oral soft tissue lesions. Due to the heterogeneity of the data, a meta-analysis was not performed. Compared to the use of cold scalpels, histological artifacts, particularly those observed in epithelial tissue, are more common when high-powered lasers are used in oral lesions biopsies. The eligibility criteria and adequate indications of high-power lasers in different oral soft tissue lesion treatments must be respected to avoid tissue artifacts that impair precise histopathological diagnosis.

The relevance of miRNAs as promising biomarkers in lip cancer.

OBJECTIVES: This study aimed to analyze the expression of miR-181b, miR-21, miR-31, and miR-345 in actinic cheilitis with and without epithelial dysplasia and lower lip squamous cell carcinomas, and to verify if the deregulated expression of these miRNAs would be indicative of malignant transformation. MATERIALS AND METHODS: The sample was selected from formalin-fixed paraffin-embedded tissues of 19 actinic cheilitis without epithelial dysplasia, 32 actinic cheilitis with epithelial dysplasia, 42 lower lip squamous cell carcinomas, and 10 nonaltered oral mucosa of the lip. The microRNA (miR, miRNA) expression was quantified by real-time RT-PCR and the expression of the selected miRNAs among the groups of actinic cheilitis and lower lip cancer was compared by chi-square. RESULTS: A higher expression of miR-181b, miR-31, and miR-345 was found in actinic cheilitis without epithelial dysplasia in comparison to that in actinic cheilitis with epithelial dysplasia and with lower lip cancer. There were no differences in miR-21 expression between actinic cheilitis and lower lip cancer. Hierarchical clustering analysis showed a tendency for a downregulation of miR-181b, miR-21, miR-31, and miR-345 in most patients with lower lip cancers. CONCLUSIONS: The upregulation of miR-181b, miR-31, and miR-345 expression in actinic cheilitis without epithelial dysplasia and the decrease in the expression of these miRNAs in actinic cheilitis with epithelial dysplasia and in lower lip cancer are potential biomarkers of malignant progression. CLINICAL RELEVANCE: This miRNA signature can help to identify actinic cheilitis with potential to progress to lip cancer.

An unusual clinical manifestation of oral melanocytic nevus.

Melanocytic nevi are acquired or congenital benign neoplasms, often found in skin but rarely in the oral mucosa. This article reports an atypical case of oral hypopigmented melanocytic nevus in a 39-year-old woman referred for evaluation of a well-circumscribed papule with discrete brownish spots in the buccal mucosa. An excisional biopsy was performed, the results of which led to a clinical diagnosis of inflammatory fibrous hyperplasia. The histopathologic analysis resulted in a diagnosis of hypopigmented intramucosal melanocytic nevus. This unusual clinical manifestation of melanocytic nevus reinforces the importance of including nonpigmented or hypopigmented melanocytic nevi in the differential diagnosis of papules arising in the oral mucosa. A biopsy and subsequent histologic examination of the specimen are recommended to establish an accurate diagnosis.

Moesin expression by tumor cells is an unfavorable prognostic biomarker for oral cancer.

BACKGROUND: Moesin is a member of the ERM (ezrin, radixin and moesin) proteins that participate in cell migration and tumor invasion through transductional signals sent to actin filaments by glycoproteins, such as podoplanin. METHODS: This study aimed to evaluate the participation of moesin and podoplanin in the invasive tumor front of oral squamous cell carcinomas, and their influence on patients' prognosis. Podoplanin and moesin immunoexpressions were evaluated by a semi-quantitative score method, based on the capture of 10 microscopic fields, at 400X magnification, in the invasive tumor front of oral squamous cell carcinomas. The association of moesin and podoplanin expression with clinicopathological variables was analyzed by the chi-square, or Fisher's exact test. The 5 and 10 years survival rates were calculated by the Kaplan-Meier method and the survival curves were compared by using the log-rank test. RESULTS: The immunohistochemical expression of moesin in the invasive front of oral squamous cell carcinomas was predominantly strong, homogenously distributed on the membrane and in the cytoplasm of tumor cells. The expression of moesin was not associated with clinical, demographic and microscopic features of the patients. Otherwise, podoplanin expression by malignant epithelial cells was predominantly strong and significantly associated with radiotherapy (p = 0.004), muscular invasion (p = 0.006) and lymph node involvement (p = 0.013). Strong moesin expression was considered an unfavorable prognostic factor for patients with oral squamous cell carcinomas, clinical stage II and III (p = 0.024). CONCLUSIONS: These results suggested that strong moesin expression by malignant cells may help to determine patients with oral squamous cell carcinoma and poor prognosis.

Podoplanin, ezrin, and Rho-A proteins may have joint participation in tumor invasion of lip cancer.

INTRODUCTION: Podoplanin and ezrin connection through Rho-A phosphorylation have been suggested as part of the activation pathway, in the process of tumor invasion and cell movement in oral squamous cell carcinomas. OBJECTIVE: The aim of this study was to evaluate the correlation among podoplanin, ezrin, and Rho-A immunoexpressions in 91 squamous cells carcinomas of the lower lip and their influence in patient's prognosis. MATERIAL AND METHODS: The immunoexpressions of podoplanin, ezrin, and Rho-A were evaluated through a semi-quantitative score method, based on the capture of 10 microscopic fields at the front of tumor invasion. The association and correlation of these proteins with the clinicopathological features were verified by Fischer's exact test and Spearman's test. The prognostic values were analyzed by Kaplan-Meier method and log-rank test. RESULTS: A statistically significant association between strong cytoplasmic podoplanin expression and alcohol (p = 0.024), loco-regional recurrences (p = 0.028), and lymph node metastasis (pN+) (p = 0.010) was found. The membranous (p = 0.000 and r = 0.384) and cytoplasmic (p = 0.000 and r = 0.344) podoplanin expression was statistically correlated with ezrin expression. Also, membranous podoplanin was significantly correlated with Rho-A expression (p = 0.006 and r = 0.282). The expressions of podoplanin, ezrin, and Rho-A were not significant prognostic factors for patients with squamous cell carcinomas of the lower lip. CONCLUSIONS: Therefore, our results confirm a correlation among podoplanin, ezrin, and Rho-A expressions in squamous cell carcinoma of the lip suggesting a cooperative participation of these proteins in cell movement and invasion. CLINICAL RELEVANCE: Furthermore, strong cytoplasmic podoplanin expression could be helpful to identify patients with squamous cell carcinoma of the lip and lower risk of loco-regional recurrences.

An Uncommon Occurrence of Three-Fourth Molars Concomitant to Hypodontia in a Nonsyndromic Patient.

Bilaterally mandibular and maxillary fourth molars, concomitant to hypodontia, are uncommon. These dental anomalies, called hypohyperdontia, are rare and etiology is not well defined. Several complications may occur as a consequence of supernumerary teeth, such as teeth impaction, resorption of adjacent teeth, and development of cysts and tumors. The authors present an uncommon occurrence of three-fourth molars concomitant to hypodontia and dentigerous cyst associated with impacted mandibular second and third molars in a nonsyndromic patient. The authors attempt to discuss the occurrence of bilaterally fourth molars and reinforce the importance of clinical approach, considering risks and benefits for the patient.

Burkitt Lymphoma in Adult With Atypical Clinical Presentation Primarily Involving the Oral Soft Tissue.

Non-Hodgkin lymphoma is the second most common neoplasm of the head and neck after squamous cell carcinoma. However, it accounts for only 3.5% of all malignancies of the oral cavity. Oral lesions are often a component of disseminated disease process that may involve regional lymph nodes or may at times represent the primary extra nodal form of the disease. Although, isolated oral lymphoma in adults is extremely rare, this paper presents a patient with Burkitt lymphoma in an adult male with atypical clinical presentation primarily involving the oral soft tissue. It is believed that the prognosis of Burkitt lymphoma depends on the extent of the disease, the patient's age, and the timing of diagnosis. Therefore, the role of the dentist in the early diagnosis and prompt referral of patients with Burkitt lymphoma cannot be overemphasized.

M2 macrophages and inflammatory cells in oral lesions of chronic paracoccidioidomycosis.

BACKGROUND: Paracoccidioidomycosis (PCM) is a systemic fungal infection caused by Paracoccidioides brasiliensis (Pb) and associated with deficient cellular immune response, which is modulated by inflammatory cells, mainly macrophages, and cytokines. Recently, the comprehension of the macrophage polarization mediated by Th1 and Th2 cytokines has contributed to elucidate the immune response that takes part in some diseases. Thus, the aim of this study was to assess the presence of Th1- and Th2-immune response and also Pb counting in oral lesions of chronic PCM. METHODS: Forty-eight cases of chronic PCM oral lesions were included. All cases were classified as loose or dense granulomas. S100 protein, IL-1ß, IL-6, TNF-α, CD163 and CD68 immunoexpressions, and Pb localization were evaluated. The fungi present in the tissue were quantified by anti-Pb antibody. RESULTS: Most patients were white men with mean age of 47 years old and showed higher incidence of multiple lesions. Loose granulomas were predominant and exhibited a great amount of M2 macrophages, which were visualized with anti-CD163 antibody. The expression for CD163 and CD68 was similar (P = 0.05), highlighting the predominance of M2 macrophages in PCM. IL-1ß, IL-6, and TNF-α immunoexpression did not significantly change with CD163, CD68, and S100 protein. The number of fungi was significantly higher in cases with intense IL-1ß immunoexpression (P = 0.003). CONCLUSIONS: M2-activated macrophages were the majority among inflammatory cells in chronic PCM, characterizing the action of a Th2-immune response. Nevertheless, Th1 cytokines were also found; mainly IL-1ß, which was associated with fungi counting in oral lesions.

Loss of cytokeratin 10 indicates malignant transformation in actinic cheilitis.

OBJECTIVES: The aim of this study was to investigate the relationship the expression of cytokeratins (CK10 and CK13) and the cell proliferation index determined by Ki-67 of lip squamous cell carcinoma and actinic cheilitis with different degrees of dysplasia. MATERIALS AND METHODS: Forty-five paraffin-embedded actinic cheilitis with and without dysplasia and 20 lip squamous cell carcinoma were analyzed by immunohistochemistry using anti-human anti-CK10, anti-CK13, and anti-Ki-67 antibodies. RESULTS: The majority of actinic cheilitis showed immunopositivity for CK10 and CK13 with decrease or loss of expression in dysplastic areas. In lip squamous cell carcinoma of the lip, heterogeneous expression of CK13 and immunonegativity for CK10 were observed. There was a statistically significant difference between CK10 expression in lip squamous cell carcinoma and in actinic cheilitis with or without dysplasia (p < 0.001). The cell proliferation index was higher in actinic cheilitis with dysplasia and lip squamous cell carcinoma than in actinic cheilitis without epithelial dysplasia. A significant correlation was found between the intensity of the epithelial dysplasia and the cell proliferation index (p < 0.001). CONCLUSION: These results provide evidence that there is a downregulation of CK10 expression in dysplastic areas of patients with actinic cheilitis and in those with lip squamous cell carcinoma (LSCC) and that the index of cell proliferation, determined by Ki-67, is directly correlated with the intensity of the epithelial dysplasia. CLINICAL RELEVANCE: Altogether, these results suggest that CK10 expression and the epithelial cell proliferation index can help to identify malignant transformation in the lip region.

Expression of E-cadherin and ß-catenin in basaloid and conventional squamous cell carcinoma of the oral cavity: are potential prognostic markers?

BACKGROUND: Basaloid squamous cell carcinoma presents with a preference for the head and neck region, and shows a distinct aggressive behavior, with frequent local recurrences, regional and distant metastasis. The alterations in the cadherin-catenin complex are fundamental requirements for the metastasis process, and this is the first study to evaluate the immunostaining of E-cadherin and ß-catenin in oral basaloid squamous cell carcinoma. METHODS: Seventeen cases of this tumor located exclusively in the mouth were compared to 26 cases of poorly differentiated squamous cell carcinoma and 28 cases of well to moderately differentiated squamous cell carcinoma matched by stage and tumor site. The immunostaining of E-cadherin and ß-catenin were evaluated in the three groups and compared to their clinicopathological features and prognosis. RESULTS: For groups poorly differentiated squamous cell carcinoma and basaloid squamous cell carcinoma, reduction or absence of E-cadherin staining was observed in more than 80.0% of carcinomas, and it was statistically significant compared to well to moderately differentiated squamous cell carcinoma (p = .019). A strong expression of ß-catenin was observed in 26.9% and 20.8% of well to moderately differentiated squamous cell carcinoma and poorly differentiated squamous cell carcinoma, respectively, and in 41.2% of basaloid squamous cell carcinoma. The 5-year and 10-year overall and disease-free survival rates demonstrated no significant differences among all three groups. CONCLUSIONS: The clinical and biological behavior of three groups of the oral cavity tumors evaluated are similar. E-cadherin and ß-catenin immunostaining showed no prognostic value for basaloid and conventional squamous cell carcinomas.

The relationship between ezrin and podoplanin expressions in keratocystic odontogenic tumors.

BACKGROUND: The aims of this study were to investigate the immunolocalization of ezrin and its relationship with the podoplanin expression in keratocystic odontogenic tumors. MATERIAL AND METHODS: The immunohistochemical expressions of ezrin and podoplanin by odontogenic epithelium were evaluated in keratocystic odontogenic tumors using monoclonal antibodies. RESULTS: Our results showed strong cytoplasmic ezrin and membranous podoplanin expressions in basal epithelial layer of all keratocystic odontogenic tumors. The cytoplasmic and membranous ezrin expressions were also detected in suprabasal epithelial layers of tumors. Statistically significant difference between cellular immunolocalization of ezrin and podoplanin odontogenic epithelium were found by Wilcoxon's test (p < 0.05). No correlation between both proteins in keratocystic odontogenic tumors was detected by Spearman test. CONCLUSIONS: These results suggest that ezrin and podoplanin may contribute to the expansive growth and local invasiveness of keratocystic odontogenic tumors. Additionally, as both proteins were overexpressed by odontogenic epithelium, their possible roles need to be further explored in benign odontogenic tumors.

Oral verruciform xanthomas mimicking potentially malignant disorders.

Verruciform xanthoma represents a reactive lesion, common in the skin and somewhat rare in the mouth. Cases description: Two cases of verrucous white plaques, located on the tongue and the floor of mouth of different 30-years-old man and woman and clinically diagnosed as leukoplakia, are described. The histopathological analyses confirmed the diagnosis of oral verruciform xanthomas for both lesions. Practical implications: Despite of uncommon in the oral cavity, the verruciform xanthoma, particularly when affecting regions with a higher risk of developing oral cancer, should be included in differential diagnosis of oral potentially malignant disorders. The histopathological analysis remains as "gold standard technique" for a more accurate diagnosis of oral verruciform xanthoma. Key words:Foam cells, Verruciform xanthoma, Leukoplakia, Tongue.

Clinical behavior of recurrent pleomorphic adenoma in the palate: a systematic review.

PURPOSE: This systematic review analyzed the clinical behavior and odds of malignancy of the palatal recurrent pleomorphic adenomas. METHODS: Systematic review of patients with recurrent pleomorphic adenoma arising in the palate. Database search: MEDLINE, Scopus, Web of Science, Cochrane, EMBASE, Virtual Health Library, Google Scholar, and OpenGrey. A binomial logistic regression was performed to assess the odds of detecting recurrence five, 10 and 20 years after the treatment of primary tumor. RESULTS: Thirteen studies (n = 18 patients) out of 336 were included. The recurrent pleomorphic adenoma in palate was more common in females (61.6%), average age was 49 years old (range 9-73 years old). Four patients progressed to malignant transformation. The odds ratio (OR) of detecting a recurrence at 10 (OR = 5.57; 95% confidence interval - 95%CI 1.13-27.52), and 20 years (OR = 18.78; 95%CI 3.18-110.84) after treatment of primary pleomorphic adenoma was significantly higher than at one-year follow-up. CONCLUSIONS: The recurrence of pleomorphic adenoma in palate remains a rare event of late occurrence. It mainly affects middle-aged female and carries a risk of malignant transformation. Although uncommon, patients with palatal pleomorphic adenoma should be warned about the possibility of recurrence or malignant transformation of tumor at advanced ages.

VEGF-C expression in oral cancer by neurotransmitter-induced activation of beta-adrenergic receptors.

The aim of this study was to investigate the expression of vascular endothelial growth factor type C (VEGF-C) in oral squamous cell carcinoma (OSCC) cell lines through norepinephrine-induced activation of beta-adrenergic receptors. Human OSCC cell lines (SCC-9 and SCC-25) expressing beta-adrenergic receptors were stimulated with different concentrations of norepinephrine (0.1, 1, and 10 µM) and 1 µM of propranolol, and analyzed after 1, 6, and 24 h. VEGF-C gene expression and VEGF-C production in the cell supernatant were evaluated by real-time PCR and by ELISA, respectively. The results showed that beta-adrenergic receptor stimulation by different concentrations of norepinephrine or blocking by propranolol did not markedly alter VEGF-C expression by SCC-9 and SCC-25 cells. VEGF-C protein levels produced by oral malignant cell lines after stimulation with different norepinephrine concentrations or blocking with propranolol was statistically similar (p > 0.05) to those of the control group (nonstimulated OSCC cell lines). Our findings suggest that stimulation of beta-adrenergic receptors by means of norepinephrine does not seem to modulate the VEGF-C expression in OSCC cell lines. These findings reinforce the need for further studies in order to understand the responsiveness of oral cancer to beta-adrenergic receptor stimulation or blockage, especially with regard to VEGF-C production.

Peculiar Histological Features of Oral Intravascular Papillary Endothelial Hyperplasia.

A 55-year-old male patient with single and well-circumscribed nodule in the lower lip. Accurate diagnosis is based only on histopathological examination using hematoxylin and eosin and immunohistochemical approach, which a large, organized thrombus within the dilated lumen of a poorly demarcated vein, associated with papillary projections of endothelial proliferation occupying vascular spaces. The final diagnosis was intravascular papillary endothelial hyperplasia (IPEH) associated with a thrombus. Oral IPEH is rare and has historically been difficult to diagnose due to its resemblance to other oral lesions. However, the distinctive histological features of oral IPEH associated with a thrombus now allow for its diagnosis through hematoxylin and eosin staining alone, without the need for additional techniques. Therefore, it is crucial for pathologists to be familiar with these unique morphological features to accurately diagnose oral IPEH and differentiate it from more common benign, malignant, or reactive vascular lesions in the oral cavity.

The role of granulocyte-macrophage colony-stimulating factor in head and neck cancer.

OBJECTIVE: To review the molecular mechanisms and biological roles of granulocyte-macrophage colony-stimulating factor (GM-CSF) in head and neck squamous cell carcinoma, highlighting its potential clinical applications. DESIGN: The search terms "granulocyte-macrophage colony-stimulating factor", "GM-CSF", "CSF2″ and "head and neck squamous cell carcinoma" or "head and neck cancer" were queried in the PubMed/MEDLINE and Scopus databases. RESULTS: Despite of being a widely expressed cytokine, the number of studies investigating the specific roles of GM-CSF in head and neck cancer was limited. Most of them investigated GM-CSF in conjunction with other cytokines. When studied alone, conflicting findings were observed in head and neck squamous cell carcinoma. GM-CSF has been shown to induce angiogenesis and local tumor invasion. Additionally, it has also been implicated in immune evasion. On the other hand, GM-CSF stimulated the differentiation of dendritic cells, which are responsible for presenting tumor antigens, and for the regulation of T cell function. Even with these paradoxical effects, there are few studies investigating the potential of GM-CSF as adjuvant therapy in head and neck cancer. CONCLUSION: The effects of GM-CSF in head and neck cancer may be pro- or antitumor. Understanding how one arm and not the other is activated is essential to assess the applicability and the safety of this cytokine as a therapeutic agent.

Subgemmal neurogenous plaque of posterolateral region in tongue: A case report and review of literature.

INTRODUCTION: The subgemmal neurogenous plaque is a well-defined subepithelial neural plexus associated with taste buds, located within foliate, fungiform, and circumvallate papillae of the human tongue, that is poorly known by dentists and medical professionals. The hyperplasia of subgemmal neurogenous plaque may occur and it manifests as a papule, nodule, plaque, or ulcer in the lateral posterior border of the tongue inducing the overdiagnosis of reactive, cystic, or neoplastic lesions. The aims of this study are to report a case of a patient with subgemmal neurogenous plaque, and to provide a comprehensive review of other subgemmal neurogenous plaque in the posterolateral tongue with challenging diagnosis. PRESENTATION OF CASE: A 28-year-old female with a little yellowish nodule, asymptomatic, located in posterior left lateral border of the tongue. Accurate diagnosis was based in excisional biopsy and histopathological examination showing a superficial neurofibroma-like pattern, and a neuroma-like in the deep zone. The final diagnosis was subgemmal neurogenous plaque. DISCUSSION: The subgemmal neurogenous plaque has an erythematous nodule or papule in the border of the tongue that are frequently misdiagnosis as foliate papillitis and lymphoepithelial cyst. Despite the subgemmal neurogenous plaque be considered a normal structure, the biopsy is recommended for differential diagnosis with other benign or malignant lesions in tongue. CONCLUSION: Contributing with the dentists and medical professionals in their clinical practice, we reviewed the literature and added a case of subgemmal neurogenous plaque in the posterolateral region of the tongue, highlighting the importance of its recognition to avoid misdiagnosis.

Relevance of Cone-beam computed tomography on diagnosis and surgical planning of the cementoblastoma.

The cementoblastoma is a rare odontogenic tumor occurring in the mandibular molar and premolar of the patients in the second and third decades of life. Despite its typical benign behavior, this tumor may promote local destruction by perforating the cortical bone and displacing the mandibular canal. This case report shows a 31-year-old man with an aggressive cementoblastoma attached to the apex of the mandibular first molar. Cone-beam computed tomography revealed a hyperdense mass connected to the root of mandibular molar surrounded by a hypodense area. Multiplanar reconstructions showed rupture of buccal bone plate and tumor invasion of the mandibular canal roof. The surgical planning included enucleation of tumor with the first and second molars extractions and the diagnosis of cementoblastoma was confirmed by histopathology. This case report emphasizes the contribution of cone-beam computed tomography on diagnosis and appropriate surgical planning of the cementoblastoma. Key words:Cone-Beam computed tomography, odontogenic tumors, diagnosis.

Bilateral jaws involvement of Burkitt's lymphoma in a pediatric patient.

A case of Burkitt's lymphoma with bilateral jaws involvement in a 5-year-old boy is reported discussing the dentist's role in the diagnosis and management of this disease. The initial clinical diagnosis established of maxillary swelling causing trismus was a dentoalveolar abscess. The incisional biopsy was performed and histopathological analysis, including immunohistochemistry, confirmed the Burkitt's lymphoma. The patient underwent treatment and remains free of the disease for 36 months of follow-up. The occurrence of intraoral bilateral jaws involvement of Burkitt's lymphoma in child is unusual and its accurate diagnosis avoids complications in the patient's treatment. Key words:Burkitt's lymphoma, Non-Hodgkin's lymphoma, Oral cavity, Maxilla, Child.

Prognostic Implications of ALDH1 and Notch1 in Different Subtypes of Oral Cancer.

BACKGROUND: The present study aimed to investigate the clinical significance and prognostic value of the immunoexpression of cancer stem cell markers, ALDH1 and Notch1, in subtypes of oral squamous cell carcinoma. MATERIALS AND METHODS: The expression of ALDH1 and Notch1 in 63 patients with well and poorly differentiated oral squamous cell carcinomas and their subtypes, verrucous carcinoma and basaloid squamous cell carcinoma, was evaluated by immunohistochemistry. The semi-quantitative analysis of the ALDH1 and Notch immunoexpression levels, based on the capture of 10 microscopic fields, at 400X magnification, at the invasive tumor front was performed and associated with clinicopathological variables using the chi-square test or Fisher's exact test. The overall and disease-free survival rates were estimated according to the Kaplan-Meier method and the curves were compared using the log-rank test. The independent effects of variables were calculated using Cox's proportional hazards regression model. RESULTS: Strong ALDH1 and Notch1 expression was observed in 16 (25.4%) and 27 (42.9%) oral squamous cell carcinomas including their subtypes, respectively. Most tumors with strong immunoexpression of ALDH1 were basaloid squamous cell carcinoma (56.3%). Statistically significant associations were observed between the strong immunoexpression of Notch1 in poorly differentiated oral squamous cell carcinoma with perineural infiltration (p = 0.011) and lymph node involvement (pN+) (p = 0.034). The strong immunoexpression of ALDH1 was a prognostic factor associated with worse overall survival (p = 0.040) for patients with oral cancer. CONCLUSION: The strong immunoexpression of Notch1 can contribute to identification of patients with poorly differentiated oral squamous cell carcinoma, who have perineural infiltration or lymph node metastasis. In addition, the strong immunoexpression of ALDH1 may help to identify a worse prognosis in patients with oral squamous cell carcinoma and their subtypes.