Predictive Role of p53 Protein as a Single Marker or Associated with ki67 Antigen in Oral Leukoplakia: A Retrospective Longitudinal Study

Validity of nomograms for predicting cancer risk in oral leukoplakia and oral lichen planus

OBJECTIVES

This study assessed the validity of nomograms for predicting malignant transformation (MT) among patients with oral leukoplakia (OL) and oral lichen planus (OLP).

MATERIALS AND METHODS

Two nomograms were identified following a systematic search. Variables to interrogate both nomograms were obtained for a retrospective OL/OLP cohort. Then, the nomograms were applied to estimate MT probabilities twice and their average was used to calculate the discriminatory performance, calibration, and potential net benefit of the models. Subgroup analyses were performed for patients with OL, OLP, and oral epithelial dysplasia.

RESULTS

Predicted probabilities were mostly significantly higher among OL/OLP patients who developed MT compared to those who did not (p = <0.001-0.034). AUC values and Brier scores of the nomograms were 0.644-0.844 and 0.040-0.088 among OL patients and 0.580-0.743 and 0.008-0.072 among OLP patients. Decision curve analysis suggested that the nomograms had some net benefit for risk stratification. However, the models did not best binary dysplasia grading in discriminatory validity and net benefit among patients with OL and oral epithelial dysplasia.

CONCLUSION

Nomograms for predicting MT may have satisfactory validity among patients with OL than OLP, but they do not outperform binary dysplasia grading in risk stratification of OL.

Inhibition of PORCN Blocks Wnt Signaling to Attenuate Progression of Oral Carcinogenesis

PURPOSE

Oral squamous cell carcinoma (OSCC) is commonly preceded by potentially malignant lesions, referred to as oral dysplasia. We recently reported that oral dysplasia is associated with aberrant activation of the Wnt/β-catenin pathway, due to overexpression of Wnt ligands in a Porcupine (PORCN)-dependent manner. Pharmacologic inhibition of PORCN precludes Wnt secretion and has been proposed as a potential therapeutic approach to treat established cancers. Nevertheless, there are no studies that explore the effects of PORCN inhibition at the different stages of oral carcinogenesis.

EXPERIMENTAL DESIGN

We performed a model of tobacco-induced oral cancer in vitro, where dysplastic oral keratinocytes (DOK) were transformed into oral carcinoma cells (DOK-TC), and assessed the effects of inhibiting PORCN with the C59 inhibitor. Similarly, an in vivo model of oral carcinogenesis and ex vivo samples derived from patients diagnosed with oral dysplasia and OSCC were treated with C59.

RESULTS

Both in vitro and ex vivo oral carcinogenesis approaches revealed decreased levels of nuclear β-catenin and Wnt3a, as observed by immunofluorescence and IHC analyses. Consistently, reduced protein and mRNA levels of survivin were observed after treatment with C59. Functionally, treatment with C59 in vitro resulted in diminished cell migration, viability, and invasion. Finally, by using an in vivo model of oral carcinogenesis, we found that treatment with C59 prevented the development of OSCC by reducing the size and number of oral tumor lesions.

CONCLUSIONS

The inhibition of Wnt ligand secretion with C59 represents a feasible treatment to prevent the progression of early oral lesions toward OSCC.

Biological biomarkers of oral cancer

The oral squamous cell carcinoma (OSCC) 5 year survival rate of 41% has marginally improved in the last few years, with less than a 1% improvement per year from 2005 to 2017, with higher survival rates when detected at early stages. Based on histopathological grading of oral dysplasia, it is estimated that severe dysplasia has a malignant transformation rate of 7%-50%. Despite these numbers, oral dysplasia grading does not reliably predict its clinical behavior. Thus, more accurate markers predicting oral dysplasia progression to cancer would enable better targeting of these lesions for closer follow-up, especially in the early stages of the disease. In this context, molecular biomarkers derived from genetics, proteins, and metabolites play key roles in clinical oncology. These molecular signatures can help predict the likelihood of OSCC development and/or progression and have the potential to detect the disease at an early stage and, support treatment decision-making and predict treatment responsiveness. Also, identifying reliable biomarkers for OSCC detection that can be obtained non-invasively would enhance management of OSCC. This review will discuss biomarkers for OSCC that have emerged from different biological areas, including genomics, transcriptomics, proteomics, metabolomics, immunomics, and microbiomics.

A 13-Gene DNA Methylation Analysis Using Oral Brushing Specimens as an Indicator of Oral Cancer Risk: A Descriptive Case Report

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.

Improvement in the risk assessment of oral leukoplakia through morphology-related copy number analysis

Oral leukoplakia is the most common type of oral potentially malignant disorders and considered a precursor lesion to oral squamous cell carcinoma. However, a predictor of oral leukoplakia prognosis has not yet been identified. We investigated whether copy number alteration patterns may effectively predict the prognostic outcomes of oral leukoplakia using routinely processed paraffin sections. Comparison of copy number alteration patterns between oral leukoplakia with hyperplasia (HOL, n=22) and dysplasia (DOL, n=21) showed that oral leukoplakia with dysplasia had a higher copy number alteration rate (86%) than oral leukoplakia with hyperplasia (46%). Oral leukoplakia with dysplasia exhibited a wider range of genomic variations across all chromosomes compared with oral leukoplakia with hyperplasia. We also examined a retrospective cohort of 477 patients with oral leukoplakia with hyperplasia with detailed follow-up information. The malignant transformation (MT, n=19) and leukoplakia recurrence (LR, n=253) groups had higher frequencies of aneuploidy events and copy number loss rate than the free of disease (FD, n=205) group. Together, our results revealed the association between the degree of copy number alterations and the histological grade of oral leukoplakia and demonstrated that copy number alteration may be effective for prognosis prediction in oral leukoplakia patients with hyperplasia.

Application of a non-invasive oral brushing procedure based on bisulfite sequencing of a 13-gene panel to study high-risk OSCC patients

BACKGROUND

A non-invasive sampling procedure for the early detection of Oral Squamous Cell Carcinoma (OSCC) based on DNA methylation analysis of a panel of 13 genes was applied in 4 different OSCC risk-group of patients. Aim of the study is to evaluate the between-group differences and the variables related to the methylation profile of each group.

METHODS

Oral brushing samples were collected from 54 healthy subjects, 31 Oral Leukoplakia (OL) patients, 18 Oral Lichen Planus (OLP) patients and 26 patients previously treated for OSCC. Each sample was considered positive or negative in relation to a predefined cut-off value.

RESULTS

None of the samples from 54 healthy subjects were positive, whereas 22/31 OL, 3/18 OLP and 8/26 surgically treated OSCC samples showed positive values with respect to the cut-off. In OL patients, dysplasia was the only variable significantly related to positive values: 10/10 OLs with high-grade dysplasia were positive with respect to 12/21 OLs without dysplasia (Chi 6.039, p< 0.05).

CONCLUSION

DNA methylation analysis in epithelial cells collected by oral brushing seems to be a promising genetic method to distinguish lesions at high risk of developing OSCC. Larger population studies and an adequate follow-up period are necessary to confirm these preliminary data.

Difficulties in the Prognostic Study of Oral Leukoplakia: Standardisation Proposal of Follow-Up Parameters

Oral leukoplakia is the most prevalent potentially malignant disorder of the oral cavity. To evaluate its potential for malignancy, appropriate documentation of the biological parameters is crucial, allowing the patients' progression to be assessed. We hypothesized a lack of standardization in the parameters employed for the prognostic study of oral leukoplakia; our aims were to determine the different parameters used for follow-up according to definition, importance, and frequency of use, and to provide a standardization proposal of follow-up research. We made a scoping review to identify papers with the keywords “leukoplakia,” “oral,” and “follow-up” published until June 2019 in English, Spanish and Portuguese literature through an online search in PUBMED, SCIELO, and SCOPUS databases. In total, 514 articles were initially identified, and fifty-nine publications were selected, of which 37 were retrospective. The reports included a total of 18,660 patients between 13 and 98 years old, with a mean age of 57.6 years. Tobacco and alcohol habits were positive for 77 and 37% of the patients, respectively. Our results showed that reported leukoplakias were predominantly located on buccal mucosa (40.4%), were homogeneous (60.8%), multiple (59.9%), smaller than 2 cm (74.4%) and histopathologically non-dysplastic (71%). The mean follow-up time was 55 months, with a 13% malignant transformation rate. The categorization and definition of multiple variables were notably diverse. Age, sex, habits (tobacco and alcohol), site, size, distribution, morphology, degree of dysplasia, and evolution were the chosen parameters for our proposal. The current study reflected the lack of consensus found in the literature regarding parameters for diagnosis or follow-up, impacting negatively on clinical and research results. standardization comprises an efficient way to facilitate the prognosis assessment of oral leukoplakia, being beneficial for clinical practice, and enabling better quality information to apply in research.

Tissue biomarkers for predicting the risk of oral cancer in patients diagnosed with oral leukoplakia: A systematic review

OBJECTIVES

We performed a systematic review to evaluate the published biomarkers related to oral leukoplakia (OL), aiming to identify the biomarkers that indicate any future risk of cancer in patients with oral leukoplakia.

METHODS

A search strategy was developed for three main electronic databases: PubMed, Cochrane Library, and EBSCO, and also for Google Scholar, until February 28, 2020. The study selection was performed in a two-phase process aiming at studies assessing tissue biomarkers for "malignant transformation of OL." Risk of bias analysis of included studies was performed using the Quality in Prognosis Studies Tool.

RESULTS

From 3,130 articles initially identified by searching databases, a total of 46 studies were included in this systematic review, with a combined sample of 3,783 patients, of whom 1,047 presented with malignant transformation of a previously diagnosed OL as reported by the authors. The cancer incidence in the whole group was 27.6% (range: 5.4% to 54.1%). The studies were derived from different geographic areas, including Asia (n = 21), Europe (n = 15), North America (n = 9), and Oceania (n = 1). There were 49 different molecular biomarkers evaluated in the 46 included studies: p53 and podoplanin proteins were the most frequently reported, followed by abnormalities at particular chromosomal loci (e.g., LOH). Risk of bias analysis revealed concerns associated with "measurement of prognostic factor," "study confounding" and "statistical analysis and reporting."

CONCLUSIONS

Substantial heterogeneity and lack of standardized reporting of data among the studies were identified. The most promising biomarkers reported to have a significant association with the malignant transformation in OL included podoplanin and chromosomal loci abnormalities. A critical examination of the follow-up studies on OL published so far indicated that tissue biomarkers that could predict the risk of oral cancer in patients with OL are still in a discovery phase.

Oral leukoplakia and the long-term risk of upper gastrointestinal cancer deaths in the Linxian dysplasia population

BACKGROUND

To investigate oral leukoplakia (OL) and risk of upper gastrointestinal (UGI) cancer deaths in the Linxian Dysplasia Nutrition Intervention Trial (NIT) cohort.

METHODS

A total of 3318 subjects with esophageal squamous dysplasia enrolled on 1 May 1985, and were followed up until 30 September 2015. Participants with OL at baseline were treated as an exposed group, while the remainder was selected as a control group. All subjects were followed monthly and reviewed quarterly by the Linxian Cancer Registry. Cox proportional hazard model was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs).

RESULTS

During the 30-year follow-up, a total of 902 UGI cancer deaths occurred, including 541 esophageal squamous cell carcinoma (ESCC) related, 284 gastric cardia carcinoma (GCC) related, and 77 gastric noncardia carcinoma (GNCC) related deaths. Relative to subjects without OL, the long-term risk of ESCC mortality in participants with OL increased by 26.1% (HR = 1.26, 95% CI: 1.05-1.52). In the subgroup analyses, adverse effects of OL on ESCC mortality were observed especially in younger subjects (HR = 1.48, 95% CI: 1.11-1.97), females (HR = 1.44, 95% CI: 1.11-1.89), non-smokers (HR = 1.44, 95% CI: 1.15-1.81), nondrinkers (HR = 1.28, 95% CI: 1.04-1.57), and individuals with a family history of cancer (HR = 1.37, 95% CI: 1.05-1.79). No associations were observed between OL and risk of GCC and GNCC mortality.

CONCLUSIONS

OL may increase the long-term risk of ESCC mortality, especially in younger subjects, females, nondrinkers, non-smokers, and subjects with a family cancer history. Future studies are needed to explore the potentially etiological mechanism.

Oral potentially malignant disorders: A scoping review of prognostic biomarkers

This scoping review aimed to map evidence regarding biomarkers for malignant transformation of oral potentially malignant disorders (OPMD). Seventy-three longitudinal studies investigating prognostic biomarkers for OPMD malignant transformation were included, encompassing 5612 disorders and 108 biomarkers, of which 72 were investigated by immunohistochemistry. Most biomarkers were assessed in one or two studies, while five (p53, Ki-67, podoplanin, p16, and DNA ploidy) were analyzed in five or more studies. All studies investigating podoplanin (n = 8) reported a significant association between positive/high immunoexpression and malignant transformation. Similarly, all studies assessing DNA ploidy (n = 5) found that aneuploidy or gross genomic aberrations were significantly associated with malignant transformation. Included studies often presented mixed data from different OPMD subtypes, inadequate description of population characteristics, and lack of adjusted analysis for confounding factors. One hundred and eight biomarkers were identified and, from these, podoplanin immunoexpression and DNA ploidy were considered promising candidates for future long-term clinical research.

World Workshop on Oral Medicine VII: Prognostic biomarkers in oral leukoplakia and proliferative verrucous leukoplakia-A systematic review of retrospective studies

OBJECTIVE

To systematically review retrospective studies examining prognostic potentials of candidate biomarkers to stratify malignant progression of oral leukoplakia (OL) and proliferative verrucous leukoplakia (PVL).

MATERIALS AND METHODS

A systematic literature search of PubMed, EMBASE, Evidence-Based Medicine and Web of Science databases targeted literature published through 29 March 2018. Inter-rater agreement was ascertained during title, abstract and full-text reviews. Eligibility evaluation and data abstraction from eligible studies were guided by predefined PICO questions and bias assessment by the Quality in Prognosis Studies tool. Reporting followed Preferred Reporting Items for Systematic Review and Meta-Analysis criteria. Biomarkers were stratified based on cancer hallmarks.

RESULTS

Eligible studies (n = 54/3,415) evaluated 109 unique biomarkers in tissue specimens from 2,762 cases (2,713 OL, 49 PVL). No biomarker achieved benchmarks for clinical application to detect malignant transformation. Inter-rater reliability was high, but 65% of included studies had high "Study Confounding" bias risk.

CONCLUSION

There was no evidence to support translation of candidate biomarkers predictive of malignant transformation of OL and PVL. Systematically designed, large, optimally controlled, collaborative, prospective and longitudinal studies with a priori-specified methods to identify, recruit, prospectively follow and test for malignant transformation are needed to enhance feasibility of prognostic biomarkers predicting malignant OL or PVL transformation.

Expression of P53 Protein and Ki-67 Antigen in Oral Leukoplakia with Different Histopathological Grades of Epithelial Dysplasia

Aims and Objective:

The aim of this study is to investigate the expression of p53 protein and Ki-67 antigen in normal oral mucosa and oral leukoplakia with different grades of dysplasia using immunohistochemistry and to clarify the correlation of the expression of these cell cycle regulatory proteins.

Materials and Methods:

A total of 20 archival tissue blocks obtained from our department which were diagnosed as mild (n = 5), moderate (n = 5), and severe dysplasia (n = 5) with normal mucosa (n = 5) as a control. Positivity of Ki-67 and p53 was analyzed using Statistical Package for the Social Sciences (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0 Armonk, NY:IBM Corp) software.

Results:

All samples showed positive staining for p53 and Ki-67. Statistically significant difference (P < 0.05) was seen between the frequency of occurrence of p53 and Ki-67 pattern of expression among all the groups. The intensity of staining was mild to intense in basal layer as there was a progression toward the severity of the disease. Almost 81.1% correlation existed between p53 and Ki-67 with high correlation and marked relationship.

Conclusion:

Oral leukoplakia represents the most common oral potentially malignant disorder (OPMD). Molecular biological markers such as p53 and Ki-67 are considered to be of great value in the diagnosis and prognostic evaluation of OPMD. Our results emphasize the potential use of p53 protein and Ki-67 antigen as significant molecular markers for early detection of PMDs and its risk of developing oral squamous cell carcinoma.

Sextuple Tumors in Head and Neck Area: Evidence of Field Cancerization

Background

Field cancerization is a phenomenon in which prolonged exposure to carcinogens induces changes throughout the epithelium leaving the field ready for the appearance of premalignant or malignant lesions. These alterations can promote the development of multiple carcinomas and explain the appearance of recurrences and second primary tumors. The objective of this study was to report the case of a patient who developed six oral cavity tumors in five years of treatment and, also, demonstrate the immunohistochemical changes for p53 and Ki-67, routinely used to assess dysplasic regions.

Case Report

When altered, p53 and Ki-67 suggest the presence of field cancers, an area with genetically altered cells, presenting a high risk of developing premalignant and malignant lesions. This phenomenon explains the recurrence of malignant neoplasms after tumor resections.

Conclusion

In addition, early identification of potentially malignant lesions in cases of second primary tumors is essential for effective treatment and patient survival, which usually have an unwelcoming prognosis.

Alterations in the expression of DNA damage response-related molecules in potentially preneoplastic oral epithelial lesions

OBJECTIVES

The aim of this study was to evaluate the expression levels of DNA damage response (DDR) markers in potentially preneoplastic oral epithelial lesions (PPOELs).

STUDY DESIGN

Immunohistochemical expression of DDR markers (γΗ2 ΑΧ, pChk2, 53 BP1, p53, and phosphorylated at Ser 15 p53) was assessed in 41 oral leukoplakias, ranging from hyperplasia (H) to dysplasia (D) and in comparison with oral squamous cell carcinoma (OSCC) and normal mucosa (NM). Statistical and receiver operating characteristic curve analysis were performed.

RESULTS

γH2 AX immunoexpression demonstrated a gradual increase and upper layer extension from NM to H to higher D degrees to OSCC. pChk2 expression was minimal in NM, relatively low in PPOELs, with an increasing tendency from H to D, and higher in OSCC. 53 BP1 demonstrated higher levels in OSCC than in NM, whereas its expression in PPOELs was heterogeneous, gradually increasing according to D. p53 demonstrated progressively higher levels and upper layer extension from H to D to OSCC. Phosphorylated p53 was absent in NM and relatively low in PPOELs and OSCC.

CONCLUSIONS

DDR markers' expression is variable in PPOELs, showing a tendency to increase along with dysplasia. Activated DDR mechanisms may play an important protective role at early stages of oral carcinogenesis, but probably suffer progressive deregulation, eventually failing to suppress malignant transformation.

Podoplanin expression as a predictive marker of dysplasia in oral leukoplakia

PURPOSE

Recent studies have emphasized the role of podoplanin in oral lesions at risk of malignant transformation. We investigated a group of oral leukoplakias (OLs) to determine a possible relation between altered podoplanin expression and dysplasia, and to compare the results with those obtained by other, widely used biomarkers.

MATERIALS AND METHODS

The population consisted of 40 consecutive patients with a clinical and histological diagnosis of OL. Thirty-two OLs did not show dysplasia, whereas eight lesions presented with dysplasia. Immunohistochemical expression of podoplanin, p53 and Ki67 was analyzed in all samples.

RESULTS

All three biomarkers were positive in seven of eight dysplastic OLs. Among the 32 OLs without dysplasia, Ki67 and p53 showed positive values in 21 and 10 samples respectively, whereas podoplanin was positive in only one case. Multiple logistic regression showed that podoplanin was the most powerful variable (Chi square 9.77; p < .01) statistically related to the presence of dysplasia. In addition, podoplanin showed a higher specificity value (96.87%) than Ki67 (34.37%) and p53 (68.75%).

CONCLUSION

Podoplanin seems to be a reliable means of discriminating lesions with epithelial dysplasia and could be introduced in routine practice as a marker to discriminate OLs at risk of developing cancer.

Toward the use of precision medicine for the treatment of head and neck squamous cell carcinoma

Precision medicine is a new strategy that aims at preventing and treating human diseases by focusing on individual variations in people's genes, environment and lifestyle. Precision medicine has been used for cancer diagnosis and treatment and shows evident clinical efficacy. Rapid developments in molecular biology, genetics and sequencing technologies, as well as computational technology, has enabled the establishment of "big data", such as the Human Genome Project, which provides a basis for precision medicine. Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with a high incidence rate and low survival rate. Current therapies are often aggressive and carry considerable side effects. Much research now indicates that precision medicine can be used for HNSCC and may achieve improved results. From this perspective, we present an overview of the current status, potential strategies, and challenges of precision medicine in HNSCC. We focus on targeted therapy based on cell the surface signaling receptors epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF) and human epidermal growth factor receptor-2 (HER2), and on the PI3K/AKT/mTOR, JAK/STAT3 and RAS/RAF/MEK/ERK cellular signaling pathways. Gene therapy for the treatment of HNSCC is also discussed.

High expression of Ki-67 acts a poor prognosis indicator in locally advanced nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common head and neck malignancy in Southern China and Southeast Asia compared with Western countries. The standard treatment for NPC is radiotherapy. However, radioresistance remains a serious obstacle to satisfactory treatment, it can cause local recurrence and distant metastases in some patients after treatment by radiation. We retrospectively reviewed 108 NPC patients (7th AJCC Ⅲ-Ⅳa) who have received intensity modulated radiation therapy (IMRT) between August 2008 and January 2012 at Xiangya Hospital of Central South University. Ninety-eight patients with >60% reduction of tumor size after radiation treatment were regarded as radiation sensitive, Ten patients with <40% reduction of tumor size after radiation treatment were regarded as radiation resistant. Using immunohistochemistry, we found that the high expression rate of Ki-67 in radiation resistant and radiation sensitive patients was 80.0% and 42.6%, respectively, and the difference was statistically significant (p = 0.025). The 5-year progress free survival rates in patients with low and high expression of Ki-67 was 70.7% and 48.0%, respectively, and the difference was statistically significant (p = 0.0008). Multivariate Cox regression analysis identified that high expression of Ki-67 was an independent negative prognostic factor in nasopharyngeal carcinoma patients [Hazard ratio (95% CI), 2.098(1.101, 3.996); p = 0.024]. These results demonstrate that high expression of Ki-67 contributes to radiation resistance and acts a poor prognosis indicator in patients with locally advanced nasopharyngeal carcinoma.

Prospective Evaluation of Multimodal Optical Imaging with Automated Image Analysis to Detect Oral Neoplasia In Vivo

The 5-year survival rate for patients with oral cancer remains low, in part because diagnosis often occurs at a late stage. Early and accurate identification of oral high-grade dysplasia and cancer can help improve patient outcomes. Multimodal optical imaging is an adjunctive diagnostic technique in which autofluorescence imaging is used to identify high-risk regions within the oral cavity, followed by high-resolution microendoscopy to confirm or rule out the presence of neoplasia. Multimodal optical images were obtained from 206 sites in 100 patients. Histologic diagnosis, either from a punch biopsy or an excised surgical specimen, was used as the gold standard for all sites. Histopathologic diagnoses of moderate dysplasia or worse were considered neoplastic. Images from 92 sites in the first 30 patients were used as a training set to develop automated image analysis methods for identification of neoplasia. Diagnostic performance was evaluated prospectively using images from 114 sites in the remaining 70 patients as a test set. In the training set, multimodal optical imaging with automated image analysis correctly classified 95% of nonneoplastic sites and 94% of neoplastic sites. Among the 56 sites in the test set that were biopsied, multimodal optical imaging correctly classified 100% of nonneoplastic sites and 85% of neoplastic sites. Among the 58 sites in the test set that corresponded to a surgical specimen, multimodal imaging correctly classified 100% of nonneoplastic sites and 61% of neoplastic sites. These findings support the potential of multimodal optical imaging to aid in the early detection of oral cancer. Cancer Prev Res; 10(10); 563-70. ©2017 AACR.

p53 and ki67 as biomarkers in determining response to chemoprevention for oral leukoplakia

BACKGROUND

We performed a randomized controlled chemoprevention trial of oral leukoplakia by administrating a low dose of beta-carotene and vitamin C supplements. 17% of subjects in the experimental arm (4/23) demonstrated clinical remission (complete or partial response) at completion of the trial. The objective of this study was to determine whether baseline expression of p53 and ki67 demonstrated any differences between those responding or not responding to our intervention. A secondary objective was to elucidate any relationship between dietary factors and clinical responses.

METHODS

For this biomarker study, we included all subjects in the experimental group (n = 23) who were non-smokers. Among 16 who completed the trial for 1 year of supplementation, there were four responders and 12 non-responders at 1-year follow-up. Following immuno-staining for p53 and ki67, the percentage of positive cell nuclei were analyzed as labeling index (LI).

RESULTS

Expression of p53 was greater in basal layers than in para-basal layers. Mean para-basal LI of p53 was higher in non-responding (26.0) than in responding subjects (11.2) (P = 0.028). ki67 LIs were not significantly different in the two groups.

CONCLUSIONS

Expression of p53 was inversely related to clinical response to the supplements. Other biomarkers that may recognize subject's responsiveness to chemoprevention require further study.

Association of XRCC1 Trp194 allele with risk of breast cancer, and Ki67 protein status in breast tumor tissues

OBJECTIVES

To evaluate the role of this polymorphism as a risk factor for breast cancer in Kurdish patients and to investigate the possible association between Arg194Trp x-ray repair cross-complementing group 1 (XRCC1) gene polymorphisms with clinical and histopathological outcomes of patients with breast cancer.

METHODS

A total of 100 breast cancer patients and 200 cancer-free controls in Kurdish population of Kurdistan state admitted to Tohid Hospital, Sanandaj, Kurdistan, Iran between January 2012 and May 2015 were enrolled in this cross-sectional study. Tissue expression of estrogen receptor (ER), progesteron receptor (PR), human epidermal growth factor receptor 2 (Her2/neu), and Ki67 were evaluated by immunohistochemistry (IHC). The Arg194Trp genotypes were determined by polymerase chain reaction- restriction fragment length polymorphism method. 

RESULTS

Our data showed that the risk for breast cancer increased significantly among the Trp variant of XRCC1. Statistically significant association was found between codon 194 polymorphisms and tissue expression of Ki67.

CONCLUSION

The Trp allele of codon 194 XRCC1 is a potential risk factor for breast cancer in Kurdish ethnicity. Furthermore, effect of this polymorphism on clinical and histological features of breast cancer was significant.

The increase of oncogenic miRNA expression in tongue carcinogenesis of a mouse model

OBJECTIVES

This study investigated the oncogenic miRNA level in the tissue and biofluids in the Nitroquinoline 1-Oxide (4NQO)-induced mouse tongue carcinogenesis model for potential diagnostic or therapeutic application.

MATERIALS AND METHODS

The histological examination, immunohistochemistry, in situ hybridization, quantitative PCR analysis and bioinformatic algorithms were performed to unravel the signaling activation and miRNA expression in female murine samples.

RESULTS

The increase of miR-21 and miR-31 staining, and EGFR activation paralleled the severity of 4NQO-induced epithelial pathogenesis in tongue epithelium. A progressive increase of miR-21, miR-31 and miR-146a in both saliva and plasma samples was also noted. miR-31 was the earliest emerging miRNA in the saliva. The increase of plasma miR-146a, miR-184 and miR-372 was detectable early in the induction, and it was particularly eminent at the most advanced lesion state. The combined analysis of the multiple oncogenic miRNAs in the plasma signified a potent discriminative capacity between normal and pathological states. As the blockage of EGFR or AKT activation drastically reverted the miR-21, miR-31 and miR-146a expression induced by 4NQO in human oral carcinoma cell lines, the results implicated a mechanistic linkage of the oncogenic miRNAs' induction through EGFR/AKT activation.

CONCLUSIONS

In this study, we show the dysregulation of oncogenic miRNAs in murine tongue tumorigenesis, which simulates human counterparts. Increased multiple miRNAs in the biofluids may be valuable non-invasive markers in detecting oral carcinogenesis at an early stage. This animal model may also be useful for developing liquid biopsies and prevention strategies against oral carcinoma by abrogating EGFR or oncogenic miRNAs.

[Precision stomatology: current status and challenges]

The completion of human genome project and the progress in medical practice have inevitably lead to the development of precision medicine, which is a medical model that proposes the customization of medical care including medical decisions, practices, and/or medical products with patient's genetic background, environmental factors and life behavior being taken into account. The current work proposed precision stomatology for the first time, and by integrating data reported in recent literature, we described the current practice of precision stomatology in multiple disciplines in modem dentistry. The clinical significance of precision stomatology and its future challenges have also been discussed.