Cytopathological tests for early detection of oral carcinogenesis

Oral cancer screening using cytopathology: An advanced proposal with the Bethesda classification

BACKGROUND

Oral cancer screening requires analysis capable of detecting changes preceding the clinical manifestation. Oral cytopathology studies as an oral cancer screening have shown promising results. This study aims to evaluate the use of cytopathology in a quali-quantitative analysis using Papanicoloau staining.

METHODS

Four experimental groups were evaluated: control (CG), exposed to carcinogens (EG), potentially malignant disorder with and without epithelial dysplasia (D-OPMDG and ND-OPMDG) and oral squamous cell carcinoma (OSCCG). Oral smears were collected using a Cytobrush® and conventional exfoliative cytology.

RESULTS

Oral Papanicolaou smears from 143 individuals were analysed in 8100 images. Qualitatively, non-lesional groups exhibited minimal suspected cases (20% in CG and 5% in EG), in the OPMD groups the ability to identify altered cells was low (40% in D-OPMDG and 0% in ND-OPMDG). Conversely, a notable 100% accuracy was achieved in the OSCCG. Quantitatively, a higher percentage of anucleated and a lower percentage of intermediate cells were observed in the OPMDG; a higher proportion of parabasal/suspicious cells was observed in OSCCG. The optimal threshold for improved accuracy in detecting suspected malignancies occurs when the count of parabasal/suspicious cells exceeds 8/100 cells examined. Cytomorphometric analysis revealed a higher nucleus/cytoplasm ratio (N/C) in OSCCG, with a best cutoff point indicating enhanced accuracy in discerning suspected malignancies when exceeding 17% of cells exhibiting this elevated ratio.

CONCLUSION

It is possible to suggest updates in cytomorphometric and quantitative analysis in the modified Bethesda system for the oral cavity including objective criteria in the risk classification, therefore improving oral cancer screening.

Microsatellite Instability and Loss of Heterozygosity as Prognostic Markers in Oral Squamous Cell Carcinoma: Molecular Mechanisms, Detection Techniques, and Therapeutic Strategies

The aim of this study was to conduct a systematic review of research investigating the potential role of microsatellite instability (MSI) and loss of heterozygosity (LOH) in oral squamous cell carcinoma (OSCC), with a focus on molecular mechanisms, detection methods, and therapeutic approaches. Search for articles involved the PubMed and Scopus. Previous retrospective and prospective studies identified variations between oral cancers that exhibit microsatellite stability and LOH. In this search, 294 articles were initially retrieved. Of these, 70 were excluded due to duplication, 106 were identified as ineligible by automated tools, and 24 were excluded as they were published in languages other than English. An additional 94 articles were excluded, 32 of which focused on head and neck cancers broadly, and 8 could not be accessed due to withdrawal. Ultimately, a systematic review was conducted based on 54 selected articles. Among the chromosomes analyzed for MSI and LOH, the highest frequency of LOH was observed on chromosome 9p. The MSI subtype is particularly susceptible to immunotherapeutic methods, such as the use of anti-PD-L1 and anti-CTLA4 antibodies, owing to its strong immunogenicity and ubiquitous expression of immune checkpoint ligands. Given the distinct characteristics and clinical behavior of oral cancer with MSI compared to microsatellite stable disease, it is advisable to incorporate MSI testing into the diagnostic process for all stages of tumor development. This ensured that each patient had received precise and effective treatment.

Chromosomal Heteromorphisms and Cancer Susceptibility Revisited

Chromosomal heteromorphisms (CHs) are a part of genetic variation in man. The past literature largely posited whether CHs could be correlated with the development of malignancies. While this possibility seemed closed by end of the 1990s, recent data have raised the question again on the potential influences of repetitive DNA elements, the main components of CHs, in cancer susceptibility. Such new evidence for a potential role of CHs in cancer can be found in the following observations: (i) amplification and/or epigenetic alterations of CHs are routinely reported in tumors; (ii) the expression of CH-derived RNA in embryonal and other cells under stress, including cancer cells; (iii) the expression of parts of CH-DNA as long noncoding RNAs; plus (iv) theories that suggest a possible application of the “two-hit model” for euchromatic copy number variants (CNVs). Herein, these points are discussed in detail, which leads to the conclusion that CHs are by far not given sufficient consideration in routine cytogenetic analysis, e.g., leukemias and lymphomas, and need more attention in future research settings including solid tumors. This heightened focus may only be achieved by approaches other than standard sequencing or chromosomal microarrays, as these techniques are at a minimum impaired in their ability to detect, if not blind to, (highly) repetitive DNA sequences.