Correlation between cell cycle proteins and hMSH2 in actinic cheilitis and lip cancer

Immunohistochemical comparative analysis of IMP-3 and KI-67 in actinic cheilitis and lower lip squamous cell carcinoma

Actinic cheilitis (AC) and lower lip squamous cell carcinoma (LLSCC) exhibit epithelial alterations mainly associated with chronic ultraviolet ray exposure. Currently, it is impossible to predict which AC cases will progress to LLSCC; thus, biomolecular markers have been studied. The aim of this study was to evaluate the immunoexpression of IMP-3 and KI-67 in AC and LLSCC. Forty AC and 40 LLSCC cases were submitted to peroxidase method and quantitatively analyzed, using the following scores: 0 (0% positive cells), + 1(≤ 30%), + 2 (> 30% to ≤ 60%), and + 3 (> 60%). Results were submitted to non-parametric Mann-Whitney (U) test. A p value < 0.05 was considered to indicate statistical significance. IMP-3 immunoexpression was observed in 26 AC cases, with predominance of the score 1 (35% of cases). This protein was also positive in 22 LLSCC cases, with predominance of the score 3 (37.5% of cases). Immunoexpression of KI-67 was observed in all studied cases, with predominance of the score 2 (70% of AC cases and 57.5% LLSCC cases). The association between IMP-3 and Ki-67 immunoexpression, AC dysplastic severity and LLSCC tumoral grade revealed no significant differences. The present results demonstrate that IMP-3 and Ki-67 immunoexpression are frequent in AC and in LLSCC. Moreover, these proteins could be involved in lower lip carcinogenesis process.

Bovine Leukemia Virus Infection Affects Host Gene Expression Associated with DNA Mismatch Repair

Bovine leukemia virus (BLV) causes enzootic bovine leukosis, a malignant form of B-cell lymphoma, and is closely related to human T-cell leukemia viruses. We investigated whether BLV infection affects host genes associated with DNA mismatch repair (MMR). Next-generation sequencing of blood samples from five calves experimentally infected with BLV revealed the highest expression levels of seven MMR genes (EXO1, UNG, PCNA, MSH2, MSH3, MSH6, and PMS2) at the point of peak proviral loads (PVLs). Furthermore, MMR gene expression was only upregulated in cattle with higher PVLs. In particular, the expression levels of MSH2, MSH3, and UNG positively correlated with PVL in vivo. The expression levels of all seven MMR genes in pig kidney-15 cells and the levels of PMS2 and EXO1 in HeLa cells also increased tendencies after transient transfection with a BLV infectious clone. Moreover, MMR gene expression levels were significantly higher in BLV-expressing cell lines compared with those in the respective parental cell lines. Expression levels of MSH2 and EXO1 in BLV-infected cattle with lymphoma were significantly lower and higher, respectively, compared with those in infected cattle in vivo. These results reveal that BLV infection affects MMR gene expression, offering new candidate markers for lymphoma diagnosis.

The Mismatch Repair System (MMR) in Head and Neck Carcinogenesis and Its Role in Modulating the Response to Immunotherapy: A Critical Review

Simple Summary

The dysfunction of the mismatch repair system, an important mechanism for the detection and correction of DNA replication mistakes, may often lead to instability in the length of specific genetic sequences, known as microsatellites, and to the accumulation of mutations. Microsatellite instability is a well-known risk factor for the development of colorectal cancers and other types of tumors but is also considered a positive predictor of the immunotherapy response. Malignancies harboring such a specific genomic instability are very immunogenic because of the great number of aberrant antigens they produce. Therapies based on the blockade of specific immune checkpoints have shown to induce an effective immune response against microsatellite-unstable cancer. Many studies proved that microsatellite instability has a decisive role in the carcinogenesis and the malignant progression of head and neck cancer and, in the near future, it may become a useful tool in tailoring immunotherapy also in this field of precision oncology.

Abstract

The mismatch repair (MMR) system has a major role in the detection and correction of DNA replication errors, resulting from DNA polymerase slippage or nucleotides misincorporation. Specific inherited/acquired alterations or epigenetic inactivation of MMR genes are associated with microsatellite instability (MSI): the loss of crucial function in repairing DNA alterations can promote carcinogenesis by favoring the accumulation of thousands of mutations in a broad spectrum of different anatomic sites such as colon, stomach, prostate, esophagus, endometrium, lung and head and neck. Recent extensive data suggest that tumor mutational burden strongly correlates with a clinical response to immunotherapy using checkpoint inhibitors and this response is influenced by MMR deficiency in a wide range of human solid cancers. In this context, few data about this crucial point are available for head and neck cancer (HNC). In this review, we discuss the role of MMR alterations and the resulting MSI in HNC pathogenesis. Furthermore, by summarizing the clinical available data on how they influence the progression of precancerous lesions and the risk of recurrence or second primary tumors, we want to define the current role of MSI in the management of HNC. Finally, we analyze the complex interaction between cancer cells and the immune system addressing the data now available about a potential correlation between microsatellite instability and immunotherapy response in HNC.

Modification in CLIC4 Expression is Associated with P53, TGF-β, TNF-α and Myofibroblasts in Lip Carcinogenesis

Chloride intracellular channel-4 (CLIC4) is regulated by p53 and tumor necrosis factor-α (TNF-α), it is linked to the increase of transforming growth factor-β (TGF-β), and myofibroblastic differentiation in skin carcinogenesis. This study analyzed the immunoexpression of CLIC4, p53, TGF-β, TNF-α, and α-SMA in 50 actinic cheilitis (AC) and 50 lower lip squamous cell carcinoma (LLSCC). AC and LLSCC immunoexpression were categorized as score 1 (<5% positive cells), 2 (5-50%) or 3 (>50%). For CLIC4, nuclear and cytoplasmic immunostaining of epithelial cells was considered individually. For morphologic analysis, the World Health Organization criteria were used to epithelial dysplasia grade of ACs, and Bryne grading of malignancy system was applied for LLSCC. Higher nuclear CLIC4 (CLIC4n) and TGF-β were observed in ACs with low-risk of transformation, while cytoplasmic CLIC4 (CLIC4c), p53 and TNF-α were higher in the high-risk cases (p<0.05). In LLSCCs, CLIC4c was higher in cases with lymph node metastasis, advanced clinical stages, and histological high-grade malignancy. p53 expression was higher in high-grade LLSCCs, whereas TGF-β decreased as the clinical stage and morphological grade progressed (p<0.05). ACs showed an increased expression of CLIC4n and TGF-β, while CLIC4c and α-SMA were higher in LLSCCs (p<0.0001). Both lesions showed negative correlation between CLIC4n and CLIC4c, while in LLSCCs, negative correlation was also verified between CLIC4c and p53, as well as CLIC4c and TGF-β (p<0.05). Change of CLIC4 from the nucleus to cytoplasm and alterations in p53, TGF-β, TNF-α, and α-SMA expression are involved in lip carcinogenesis.

Can immunohistochemical biomarkers distinguish epithelial dysplasia degrees in actinic cheilitis? A systematic review and meta-analysis

BACKGROUND

Actinic cheilitis (AC) is a potentially malignant disorder of the lip, characterized by epithelial and connective tissue alterations caused by chronic exposure to ultraviolet radiation. In the past decades, diverse studies have been conducted in lip carcinogenesis and many biomarkers have been identified in lip lesions, yet there is no scientific evidence that determines its usefulness in the clinical setting or in histopathological routine. Therefore, we conducted the first systematic review in this field to summarize the results of published studies on immunohistochemical biomarkers in lip carcinogenesis, to evaluate if there is a marker than can distinguish the different histological grades of AC.

MATERIAL AND METHODS

Retrospective studies that investigated immunohistochemical biomarkers in AC defined on standardised histological assessment were gathered from five databases and evaluated. Each study was qualitatively evaluated using the Critical Appraisal Tools from SUMARI.

RESULTS

The proliferation marker Ki-67 was the most studied biomarker and we observed, through meta-analysis, that it was differently expressed between AC and lip cancer, but not in AC subgroups. Most articles had a high risk of bias.

CONCLUSIONS

In summary, the literature lacks quality follow up studies in actinic cheilitis. Multi-centre cohort studies, with patients stratified by treatment type and the use of image analysis software, could be the solution to further address the issues of investigating potentially malignant lesions and help change clinical practice, in terms of individualizing patients' treatment and prognosis prediction.

Involvement of repair genes in oral cancer: A systematic review

Among the types of cancers that may occur in the oral cavity, squamous cell carcinomas (SCC) of the mouth have a higher incidence and are associated with increased rates of morbidity and mortality. Among steps from the beginning to the progression of the tumour, DNA Repair System is highlighted. The present study aims to conduct a systematic review of the literature on the expression of the repair genes hMSH2 and hMSH6 in patients with SCC in the mouth and oropharyngeal region. The search was performed in databases such as PubMed, Lilacs, and Scielo and included articles published in English from 1999 until 2015. The search in the above-mentioned databases initially yielded 15 scientific articles related to the proposed objective. After a detailed analysis of each of them, only 8 were included in the present review, precisely because they met the inclusion criteria determined in the method. All the reviewed works were unanimous in recognizing the veracity and complexity of the Genomic Repair System, also called Mismatch Repair System, confirming the participation of repair gene proteins (such as hMSH2 and hMSH6) in patients with oral cancer and even of lesions that are susceptible to malignization. SIGNIFICANCE OF THE STUDY: Worldwide, there are an estimated 300 thousand new cases of oral cancer per year. Studies have shown a greater risk in individuals who are smokers and alcohol consumers in developing mouth cancer. Many steps are observed from the beginning to the progression of the tumour, highlighted among them is the moment in which genetic, and epigenetic alterations will interfere in the functioning of the DNA Repair System. This work presents a survey of current knowledge about the involvement of repair genes, especially those of the MutSα system, in the development and progression of oral cancer.

Immunoexpression of cleaved caspase-3 shows lower apoptotic area indices in lip carcinomas than in intraoral cancer

OBJECTIVE

This study aimed to evaluate apoptosis by assessing cleaved caspase-3 immunoexpression in hyperplastic, potentially malignant disorder (PMD), and malignant tumors in intraoral and lower lip sites.

MATERIAL AND METHODS

A retrospective study using paraffin blocks with tissues from patients with inflammatory fibrous hyperplasia (IFH), actinic cheilitis, oral leukoplakia, lower lip and intraoral squamous cell carcinoma (SCC) was performed. The tissues were evaluated by immunohistochemical analysis with anti-cleaved caspase-3 antibody. Apoptotic area index was then correlated with lesion type.

RESULTS

From 120 lesions assessed, 55 (46%) were cleaved caspase-3-positive. The SCC samples (n=40) had the highest apoptotic area indices (n=35; 87.5%). Significant differences were detected between SCCs and PMDs (p=0.0003), as well as SCCs and IFHs (p=0.001), regarding caspase-3 immunopositivity. Carcinomas of the lower lip had lower apoptotic area indices than intraoral cancer (p=0.0015).

CONCLUSIONS

Cleaved caspase-3 immunoexpression showed differences in oral SCCs and PMDs and demonstrated a distinct role of apoptosis in carcinogenesis of intraoral and lower lip cancer. In future, the expression of cleaved caspase-3 with other target molecules in oral cancer may be helpful in delineating the prognosis and treatment of these tumors.