Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumours with increasing incidence, and oral leukoplakia (OLK) has a strong tendency to undergo malignant transformation. The oral microbiota may influence oral cancer progression, but the salivary bacterial composition and functional changes in OSCC and OLK have not been comprehensively elucidated. Therefore, we compared salivary bacteria in OLK and OSCC patients with healthy controls (HC).
Metagenomic sequencing was used to compare the bacterial composition and functional changes of 18 OSCC patients, 21 OLK patients and 21 HC. Spearman correlation was used to identify possible associations between functions and bacteria.
Gemella was the most differentially enriched genus in OSCC. At the species level, Streptococcus sp. NPS 308, Streptococcus agalactiae, Gemella haemolysans and Gemella morbillorum were slightly increased in OLK and OSCC. Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that OSCC was mainly associated with metabolism functions, including lipid metabolism, carbohydrate metabolism and glycan biosynthesis and metabolism. The synthesis and degradation of ketone bodies, cysteine and methionine metabolism and glycerolipid metabolism differed significantly among the three groups, and were highest in OSCC and lowest in HC. And G. haemolysans was significantly associated with these selected metabolic pathways.
Metagenomic analysis revealed significant differences in the salivary microbiota among OSCC, OLK and HC. Thus, salivary microbiota composition and functional changes may be associated with OSCC progression. Metabolism of nonessential amino acids such as cysteine and methionine in bacteria may play an important role in oral oncogenesis, and more studies of the mechanism between metabolisms of bacteria and oral oncogenesis are needed in the future.

暂无摘要。

BACKGROUND: Oral leukoplakia and oral submucous fibrosis are potentially malignant disorders of the oral cavity, with high rates of recurrence and malignant transformation. Notably, the malignant transformation rate of oral leukoplakia with concomitant oral submucous fibrosis is significantly higher than that of oral submucous fibrosis or oral leukoplakia alone. However, the management of these conditions is not well defined. Photodynamic therapy is a minimally invasive treatment modality that effectively targets oral potentially malignant disorders, such as oral leukoplakia, erythroleucoplakia, and verrucous hyperplasia, with the advantages of being repeatable and leaving no scarring.
METHODS: We report the case of a 42-year-old man with concomitant oral leukoplakia and oral submucous fibrosis almost involving the entire right buccal mucosa, who underwent six sessions of topical 5-aminolevulinic acid-mediated photodynamic therapy.
RESULTS: Photodynamic therapy successfully eradicated whitish plaques and improved mouth opening without any adverse effects. Although photodynamic therapy failed to completely reverse the pathological changes, grading of epithelial dysplasia did not progress and clinical recurrence was not found during the 10-month follow-up.
CONCLUSIONS: In conclusion, topical 5-aminolevulinic acid-mediated photodynamic therapy appears safe and has excellent clinical efficacy against oral leukoplakia-concomitant oral submucous fibrosis, but long-term follow-up is necessary.

Oral leukoplakia (OL) and oral submucosal fibrosis (OSMF) are precancerous conditions with common etiologies but with different risks for oral cancer (OC) progression. In rare cases, both conditions occur in the same patient and provide an opportunity for understanding the common and distinctive variants upon exposure of genetically identical normal cells to the same carcinogen(s). We performed exome sequencing of a patient with OL (hyperplasia, but no dysplasia) and OSMF (grade II) in the opposite cheeks using blood DNA as the reference genome. The overall somatic variant burden was higher in OSMF than OL, but opposite in the case of copy number alterations. OL-specific variants were enriched in genes associated with DNA repair, cell division/cell cycle checkpoint pathways, whereas in OSMF, extracellular matrix-receptor interaction was mainly affected. The proportions of variants in cancer driver genes and cancer driver mutations were similar in both cases indicating no difference in the potential risk associated with the two conditions at the stages sampled. Future studies on rare cases similar to the one described in this report will help in understanding the molecular basis of differences associated with OL and OSMF and shared processes accompanying OC progression.

Analysis of genetic or epigenetic markers from saliva or brushing specimens has been proposed as a diagnostic aid to identify patients at risk of developing oral cancer. However, no reliable non-invasive molecular method for this purpose is commercially available. In the present report, we describe the potential application of a procedure based on a 13-gene DNA methylation analysis using oral brushing samples from a patient affected by oral leukoplakia who developed two metachronous oral carcinomas during the follow-up period. A positive or a negative score was calculated for each brushing sample based on a predefined cut-off value. In this patient, a positive score was detected in the oral leukoplakia diagnosed more than 2 years before the development of oral squamous cell carcinoma and subsequently in clinically healthy mucosa 8 months before the appearance of a secondary tumor. This suggests a potential role of our procedure as an indicator of oral cancer risk.

The aim of this report was to describe a rare case of leukoplakia in a young patient without any risk factors for squamous cell carcinoma. An 18-year-old male patient presented with an asymptomatic white lesion on the right lateral border of the tongue. Microscopic examination of the excisional biopsy specimen displayed hyperkeratosis and acanthosis without epithelial dysplasia, which were consistent with the clinical diagnosis of oral leukoplakia. The patient is undergoing systematic and regular evaluation, and after 28 months of follow-up, no recurrence has been observed. This report showed that, although uncommon, adolescents and/or young adults can also be affected by oral potentially malignant disorders. Therefore, dentists should be aware of this condition to establish the proper diagnosis and management.

Oral leukoplakia (OL) has the potential for malignant transformation; unfortunately, there are no strategies to prevent this possible outcome. Surgical intervention has been reported to be effective in reducing but not eliminating the risk of malignant transformation. Meta-analyses have reported that patients who underwent excision of OL lesions had a significantly lower chance of malignant transformation than those whose lesions were not excised. The present study aimed to report a case of successful management of extensive OL using a high-power laser. The patient has been under periodic monitoring, and we aim to continue the follow-up as long as possible. Recurrence or signs of malignancy were not observed at the 2-year follow-up.

OBJECTIVE: The purpose of this study was to investigate the presence of chronic diseases in patients with oral leukoplakia (OL) compared to controls matched for age group, gender, smoking and alcohol use.
METHODS: This case-control study examined the general demographics, medical and social histories of 105 OL cases and 391 controls matched for age group, gender, tobacco and alcohol use. All OL cases were diagnosed based on both clinical and histopathological findings.
RESULTS: Chronic diseases were significantly associated with OL, namely dyslipidaemia (p < .0001), musculoskeletal diseases (p = .0101) and asthma (p = .0052). The use of ACE inhibitors (p = .0177), opioid analgesics (p = .0300), anticoagulants (p = .0055) and statins (p = .0010) was significantly associated with OL. Dyslipidaemia (p < .0001; odds ratio [95% CI]: 6.4 [3.5-11.6]) and asthma (p = .0110; odds ratio [95% CI]: 2.2 [1.2-4.0]) were identified as independent predictors of OL in multivariate analysis, both of which were significantly more common amongst cases than controls.
CONCLUSIONS: Results from this first Australian study suggest that dyslipidaemia and asthma may constitute independent predictors for the presence of OL. However, longitudinal studies are needed to ascertain the temporal relationship between OL and chronic disease comorbidity and the mechanisms underlying these associations.

Oral leukoplakia (OL), a predominantly white change to the oral mucosa, is the most common potentially malignant lesion. Elimination of this condition, especially high risk OL, is advisable, even necessary as an attempt to avoid malignant transformation. Here we present three cases of OL successfully treated by ALA photodynamic therapy (PDT) following pretreatment with CO2 laser. After a series of one to three sessions the patients were monitored for 12 months. All lesions showed remission, but one recurred during follow-up. Side effects included mild edema, erosion and burning sensation. No severe side effects were observed. In summary, the combination of PDT and CO2 laser is safe and effective in the treatment of OL.

Dyskeratosis congenita (DC) is a rare genetic disorder of bone marrow failure inherited in an X-linked, autosomal dominant or autosomal recessive pattern. It has a wide array of clinical features and patients may be cared for by many medical sub specialties. The typical clinical features consist of lacy reticular skin pigmentation, nail dystrophy and oral leukoplakia. As the disease advances, patients may develop progressive bone marrow failure, pulmonary fibrosis, oesophageal stenosis, urethral stenosis, liver cirrhosis as well as haematological and solid malignancies. Several genes have been implicated in the pathogenesis of dyskeratosis congenita, with the dyskerin pseudouridine synthase 1 (DKC1) gene mutations being the X-linked recessive gene.
Herein, we report a 31-year-old male with history of recurrent febrile episodes who was found to have reticulate skin pigmentation interspersed with hypopigmented macules involving the face, neck and extremities, hyperkeratosis of palms and soles, nail dystrophy, leukoplakia of the tongue, premature graying of hair, watery eyes and dental caries. Several of his male relatives, including two maternal uncles and three maternal cousins were affected with a similar type of disease condition. Pedigree analysis suggested a possible X-linked pattern of inheritance. Genetic testing in the proband showed a novel hemizygous, non-synonymous likely pathogenic variant [NM_001363.4: c.1054A > G: p.Thr352Ala] in the PUA domain of the DKC1 gene. Quantitative polymerase chain reaction for relative telomere length measurements performed in the proband showed that he had very short telomeres [0.38, compared to a control median of 0.71 (range 0.44-1.19)], which is consistent with the DC diagnosis. Co-segregation analysis of the novel mutation and telomere length measurements in the extended family members could not be performed as they were unwilling to provide consent for testing.
The novel variant detected in the DKC1 gene adds further to the existing scientific literature on the genotype-phenotype correlation of DC, and has important implications for the clinical and molecular characterization of the disease.