Genomic Engineering of Oral Keratinocytes to Establish In Vitro Oral Potentially Malignant Disease Models as a Platform for Treatment Investigation

Precancerous cells in the oral cavity may appear as oral potentially malignant disorders, but they may also present as dysplasia without visual manifestation in tumor-adjacent tissue. As it is currently not possible to prevent the malignant transformation of these oral precancers, new treatments are urgently awaited. Here, we generated precancer culture models using a previously established method for the generation of oral keratinocyte cultures and incorporated CRISPR/Cas9 editing. The generated cell lines were used to investigate the efficacy of a set of small molecule inhibitors. Tumor-adjacent mucosa and oral leukoplakia biopsies were cultured and genetically characterized. Mutations were introduced in CDKN2A and TP53 using CRISPR/Cas9 and combined with the ectopic activation of telomerase to generate cell lines with prolonged proliferation. The method was tested in normal oral keratinocytes and tumor-adjacent biopsies and subsequently applied to a large set of oral leukoplakia biopsies. Finally, a subset of the immortalized cell lines was used to assess the efficacy of a set of small molecule inhibitors. Culturing and genomic engineering was highly efficient for normal and tumor-adjacent oral keratinocytes, but success rates in oral leukoplakia were remarkably low. Knock-out of CDKN2A in combination with either the activation of telomerase or knock-out of TP53 seemed a prerequisite for immortalization. Prolonged culturing was accompanied by additional genetic aberrations in these cultures. The generated cell lines were more sensitive than normal keratinocytes to small molecule inhibitors of previously identified targets. In conclusion, while very effective for normal keratinocytes and tumor-adjacent biopsies, the success rate of oral leukoplakia cell culturing methods was very low. Genomic engineering enabled the prolonged culturing of OL-derived keratinocytes but was associated with acquired genetic changes. Further studies are required to assess to what extent the immortalized cultures faithfully represent characteristics of the cells in vivo.

A narrative review of the role of Eph receptors in head and neck squamous cell carcinoma

Tyrosine kinase receptors (TKR) coordinate a variety of pathological processes in head and neck squamous cell carcinoma (HNSCC), and eventually play a role in patient outcomes. In this review, the role of Eph receptors in HNSCC progression and the possibility of targeting these receptors are illustrated. All relevant studies were identified through a comprehensive search of four electronic databases, including PubMed, Scopus, web of science, and Embase till August 2022. EphA2 and EphB4, along with ephrin-B2, were the most extensively studied proteins in this family. However, overexpression of EphB4 and its ligand ephrin-B2 were the only proteins that consistently showed association with a poor outcome, indicating that these proteins might serve as valuable prognostic markers in HNSCC. High expression of EphA3 and EphB4 was found to play a crucial role in radioresistance of HNSCC. EphB4 loss, in particular, was observed to induce an immunosuppression phenotypic HNSCC. Currently, ongoing clinical trials are investigating the benefits of EphB4-ephrin-B2 blockade in combination with standard of care treatment in HNSCC. Further efforts are needed to explore the biological role and behavioral complexity of this family of TKR in HNSCC with great attention to avoid heterogeneity of HNSCC subsites.

The value of regular follow-up of oral leukoplakia for early detection of malignant transformation

OBJECTIVES

Evaluate whether regular follow-up of oral leukoplakia (OL) resulted in early detection of malignant transformation (MT).

METHOD

Two hundred and twenty-two consecutive patients with OL (147 females, 75 males); median follow-up period of 64 months (range: 12-300). Three groups were distinguished: group A (n = 92) follow-up at the hospital; group B (n = 84) follow-up by their dentist; group C (n = 46) lost to follow-up.

RESULTS

OLs in group B compared to group A, were smaller in size (<2 cm; p < 0.001), showed more hyperkeratosis (p < 0.001) and less moderate/severe dysplasia (p < 0.001). MT occurred in 45 (20%) patients: 32 (35%) in group A, five (6%) in group B and eight (17%) in group C. There was no significant difference in clinical tumour size between group A (median: 15 mm, range: 1-40) and group B (median: 10 mm, range: 3-25; p = 0.496). Tumour size was smaller for patients in groups A and B (median: 10 mm, range 1-40) compared to group C (median: 33 mm, range: 3-100; p = 0.003). There was a positive correlation between tumour size and interval between the last visit in all patients (p = 0.022).

CONCLUSION

Regular follow-up of OL resulted in early detection of MT. If properly selected, follow-up of OL performed by the dentist seems feasible.

The role of differentiated dysplasia in the prediction of malignant transformation of oral leukoplakia

OBJECTIVE

Oral leukoplakia is the most common oral potentially malignant disorder. Malignant transformation of oral leukoplakia occurs at an annual rate of 1%-7%. WHO-defined classic epithelial dysplasia is an important predictor of malignant transformation of oral leukoplakia, but we have previously shown in a proof of concept study that prediction improves by incorporation of an architectural pattern of dysplasia, also coined as differentiated dysplasia. We aimed to analyze this finding in a larger cohort of patients.

METHOD

For this retrospective study 176 oral leukoplakia patients were included. Biopsies for all patients were assessed for the presence of dysplasia and analyzed for cytokeratin 13 and 17 expression. Moreover, the inter-observer agreement for the diagnosis of differentiated dysplasia was determined.

RESULTS

In total, 33 of 176 patients developed oral squamous cell carcinoma during follow-up. Presence of classic epithelial dysplasia increased cancer risk two-fold (HR = 2.18, p = 0.026). Lesions without classic epithelial dysplasia could be further risk-stratified by the presence of differentiated dysplasia (HR = 7.36, p < 0.001). Combined classic epithelial and differentiated dysplasia imparted a seven-fold increased risk of malignant transformation (7.34, p = 0.001). Inter-observer agreement for the diagnosis of dysplasia, including differentiated dysplasia, was moderate (κ = 0.56, p < 0.001).

DISCUSSION

This study emphasizes the importance of the recognition of the architectural pattern of differentiated dysplasia as a separate entity for risk prediction of malignant transformation of oral leukoplakia. Presence of any pattern of dysplasia results in accurate prediction of malignant transformation risk of oral leukoplakia.

Complications of Sialendoscopy in Patients With Sjögren Syndrome

PURPOSE

Recent literature suggests that sialendoscopy of the major salivary glands could alleviate symptoms of Sjögren syndrome (SS) and restore salivary function. The aim of this study was to evaluate the authors' experience of sialendoscopy of the salivary glands in patients with SS.

MATERIALS AND METHODS

In this retrospective case series study, the surgical data of patients with SS who had undergone sialendoscopy at the VU University Medical Center (Amsterdam, The Netherlands) from November 2014 through April 2015 were used. Outcome measurements were successful entry to the salivary gland and completion of sialendoscopy as planned. Furthermore, pre- and postoperative complications were scored. Descriptive analysis of the data was performed.

RESULTS

Surgical data of sialoendoscopic procedures in 26 patients with SS (24 women and 2 men; mean age, 57 yr; range, 27 to 72 yr) were analyzed. Sialendoscopy was successfully performed in 78 of 104 salivary glands (75%; 50 parotid and 28 submandibular glands) in the 26 patients. Sialendoscopy failed in 26 of the 104 sialoendoscopic procedures (25%; 2 parotid and 24 submandibular glands). In 16 salivary glands, the ductal orifice could not be identified. In 7 salivary glands, sialendoscopy could not be performed because of partial or complete stenosis of the salivary duct. In 3 salivary glands, sialendoscopy was not performed because of a ductal perforation. Three patients developed a postoperative infection.

CONCLUSION

The overall rate of complications was limited and the sialoendoscopic complications in patients with SS could be regarded as minor. Most complications were seen for sialendoscopy of the submandibular glands in this specific patient category. Careful preoperative selection of patients and salivary glands could contribute to a lower rate of complications and more predictable results.

Fracture of the genial tubercles of the mandible: case report and review of the literature

Fracture of the genial tubercles is a rare occurrence and can occur as a solitary fracture or an associated fracture of the mandible. A solitary fracture seems to be associated with severe atrophy of the mandible. A report of a case of fractured genial tubercles in an 80-year-old edentulous female patient is described and a review of the literature is presented.

[Sialendoscopy for obstructive disorders of the salivary glands]

Obstructive disorders of the salivary glands usually manifest as a swelling which is associated with meals ('mealtime syndrome') as well as inflammation of the gland. Obstruction of the salivary ducts of the parotid and submandibular glands is usually caused by a salivary stone, mucous plug or by a stenosis. Until recently, the options for diagnosis and treating these conditions were limited. Ultimately, the decision to remove the salivary gland was often made. Sialendoscopy is a recently developed semi-rigid optical technique that can be used to detect and usually treat obstructions in the salivary ductal system. This new, minimally invasive technique has resulted in the reduction of morbidity related to salivary gland obstruction. In many patients, surgical removal of the salivary gland can be avoided by using this technique.

[A woman with a pigmentation of the hard palate]

A bluish flat pigmented lesion of the hard palate of a 51-year-old woman was excised to exclude malignancy, in particular oral malignant melanoma. On histopathological examination, depositions of black pigment were seen accompanied by several foreign body giant cells. Probably due to a childhood trauma, a pencil point had penetrated the hard palate.

The possible premalignant character of oral lichen planus and oral lichenoid lesions: a prospective study

OBJECTIVES

The possible malignant transformation of oral lichen planus (OLP) is the subject of an ongoing and controversial discussion in the literature. The main criticism of studies on this subject relates to the lack of sufficient data to support the initial diagnosis of OLP in cases that finally developed into squamous cell carcinoma. We describe the possible premalignant character of OLP and oral lichenoid lesions (OLL) of a prospectively followed cohort of patients with detailed documentary data.

STUDY DESIGN

A study group of 173 patients, 62 patients diagnosed with OLP and 111 patients with OLL, according to revised, modified World Health Organization diagnostic criteria, was followed up from 6.6 to 72.0 months (mean, 31.9 months). The expected number of patients with oral cancer in the group of patients with OLP and in the group of patients with OLL was estimated by comparing the number of patients, their ages, sex, and the length of follow-up to annual incidence rates of oral cancer for the general Dutch population, to explore the possibility of coincidental carcinomas. The binomial test was used to determine whether the observed number of cases of cancer in the OLP group and the OLL group exceeded the expected numbers.

RESULTS

Three of 173 patients (1.7%), 2 men and 1 woman, developed squamous cell carcinomas of the oral mucosa during follow-up. All malignant transformations occurred in the OLL group. The annual malignant transformation rate, based on a mean follow-up of 31.9 months, was calculated as 0.65% per year. A comparison of the expected against actual figures for the development of carcinomas revealed no increase in patients with OLP and a 219-fold increase in patients with OLL, with the latter not statistically significant, but with a P value of .083, suggesting at least a trend.

CONCLUSION

Our results give support to the hypothesis that patients with OLL have an increased risk of oral cancer, but this increased risk was not detected in our sample of patients with OLP. Before a final statement with regard to the premalignant character of OLP and OLL can be formulated, the present follow-up study should be prolonged and expanded with a larger number of patients. Until then, we advise that patients with OLP and OLL should undergo biannual follow-up examinations. Follow-up will be particularly important in patients with OLL who have atrophic/erosive/ulcerative lesions.

Cheilitis granulomatosa: overview of 13 patients with long-term follow-up--results of management

BACKGROUND

Cheilitis granulomatosa, often regarded as a subtype of orofacial granulomatosis, is characterized by recurrent or persistent swelling of one or both lips. Classically, a non-necrotizing granulomatous inflammation is seen at histologic examination. Although a relationship has been proposed between Melkersson-Rosenthal syndrome (and the monosymptomatic form, cheilitis granulomatosa) and Crohn's disease on the basis of the orofacial swelling and similar histology, several studies of Melkersson-Rosenthal syndrome have not found an association with Crohn's disease.

METHODS

The clinical features, histopathology, association with Crohn's disease, and results of nonsurgical and surgical therapy in 13 patients with cheilitis granulomatosa were investigated in a retrospective case study with a mean follow-up period of 8.2 years.

RESULTS

There was a low chance of developing Crohn's disease. Most patients in this study responded to nonsurgical treatment modalities. Patients with deterioration of lip swelling usually responded to intralesional injections with triamcinolone or to short courses of systemic glucocorticoids. Nonsteroidal systemic modalities, such as clofazimine, hydroxychloroquine, or sulfasalazine, were alternatives to glucocorticoid regimens, thus avoiding the long-term side effects of corticosteroids. Surgical intervention should only be performed in severely disfiguring cases.

CONCLUSIONS

The management of cheilitis granulomatosa remains a challenge. As this study revealed a low chance of developing Crohn's disease, it does not seem justified to inform patients with cheilitis granulomatosa of the possibility that they might develop Crohn's disease. Patients with a negative history of gastrointestinal complaints should not be exposed to routine investigations of the gastrointestinal tract.