The role of chromatin-modifying enzymes and histone modifications in the modulation of p16 gene in fumonisin B1-induced toxicity in human kidney cells.

Fumonisin B1 (FB1) poses a risk to animal and human health. Although the effects of FB1 on sphingolipid metabolism are well documented, there are limited studies covering the epigenetic modifications and early molecular alterations associated with carcinogenesis pathways caused by FB1 nephrotoxicity. The present study investigates the effects of FB1 on global DNA methylation, chromatin-modifying enzymes, and histone modification levels of the p16 gene in human kidney cells (HK-2) after 24 h exposure. An increase (2.23-fold) in the levels of 5-methylcytosine (5-mC) at 100 µmol/L was observed, a change independent from the decrease in gene expression levels of DNA methyltransferase 1 (DNMT1) at 50 and 100 µmol/L; however, DNMT3a and DNMT3b were significantly upregulated at 100 µmol/L of FB1. Dose-dependent downregulation of chromatin-modifying genes was observed after FB1 exposure. In addition, chromatin immunoprecipitation results showed that 10 µmol/L of FB1 induced a significant decrease in H3K9ac, H3K9me3 and H3K27me3 modifications of p16, while 100 µmol/L of FB1 caused a significant increase in H3K27me3 levels of p16. Taken together, the results suggest that epigenetic mechanisms might play a role in FB1 carcinogenesis through DNA methylation, and histone and chromatin modifications.

A Red Flag: A Case of Oropharyngeal Cancer Masquerading as an Ulcer of an Infective Origin.

Oropharyngeal squamous cell carcinoma is a prevalent neoplastic condition. The incidence rate in Malaysia is rising, with human papillomavirus (HPV) infection being recognized as a significant contributing factor. Hence, it is paramount for physicians to effectively diagnose and identify significant indicators that may indicate a malignant etiology. In this study, we present a case of a middle-aged Malay male who presented with the primary symptom of persistent right throat discomfort for one month. The preliminary presentation, blood parameters, and initial histopathological examination (HPE) findings indicate the presence of an infection. However, despite undergoing several medical treatments, the patient's symptoms remain, albeit with only minor clinical improvement. Subsequently, the patient underwent a biopsy under general anesthesia, which subsequently yielded a report indicating the presence of oropharyngeal squamous cell carcinoma with a negative p16 status. Therefore, it is imperative for clinicians to possess knowledge of warning flags and exercise vigilance when encountering a patient who fails to respond despite thorough and precise evaluation. If there is a strong suspicion of malignancy, it is imperative to do a comprehensive clinical investigation and regular monitoring.

Prognostic significance of p16 protein in pancreatic ductal adenocarcinoma.

The p16 gene, which is also known as CDKN2A, INK4A, or CDK4I, and its products that are known to be cell cycle inhibitors and tumor suppressors have been reported to be altered in various human tumor types. Altered p16 has been indicated to be correlated with negative p16 expression using immunohistochemistry (IHC). However, its association with the prognosis remains controversial because the findings of previous studies are inconsistent. The current study evaluated the relationship between the expression levels of p16 and the clinicopathological features associated with prognosis in patients with primary pancreatic ductal adenocarcinomas (PDACs). From January 2013 to December 2017, tissues of 103 PDAC patients who had undergone elective pancreatic resection were obtained and assessed for p16 expression by IHC. No correlation was observed between p16 status and clinicopathological factors (P>0.05). Notably, negative p16 expression on IHC was not significantly associated with poor prognosis using the Kaplan-Meier method.

The association between PON1 and GSTM1 genetic variation with methylation of p16 gene promoter among Javanese farmers exposed to pesticides at Magelang Regency, Central Java, Indonesia.

Occupational exposure to pesticides leads to the development of cancer. Aberrant DNA methylation plays a crucial role in cancer. The manifestation of the carcinogenic effect of pesticides could be determined by the variation of genes encoding enzyme, including PON1 Q192R and GSTM1. The goal of this study was to find out polymorphism of PON1 Q192R and methylation of p16 gene promoter, and their correlation on Javanese farmers in the agricultural area of Ngablak Subdistrict, Magelang Regency, Central Java. Seventy-eight pesticide-exposed farmers enrolled in the study. Polymorphism of PON Q192R was determined using PCR-RFLP and variation of GSTM1 was examined using conventional PCR. The methylation of the p16 gene promoter was determined using methylation-specific PCR. The result revealed 94.9% polymorphism of PON1 Q192R, which was higher in the R/R (Arg/Arg) genotypes than Q/R (Gln/Arg) and lowest in Q/Q (Gln/Gln) genotypes. We also found 82.1% GSTM1 null genotype among the farmers enrolled in the study. As many as 26.9% methylations of p16 gene promoter were found among farmers. Genetic variation of PON1 Q192R and GSTM1 were not found to be correlated to the methylation status of p16 gene promoter in the Javanese population.

DNA hydroxymethylation increases the susceptibility of reactivation of methylated P16 alleles in cancer cells.

It is well established that 5-methylcytosine (5mC) in genomic DNA of mammalian cells can be oxidized into 5-hydroxymethylcytosine (5hmC) and other derivates by DNA dioxygenase TETs. While conversion of 5mC to 5hmC plays an important role in active DNA demethylation through further oxidation steps, a certain proportion of 5hmCs remain in the genome. Although 5hmCs contribute to the flexibility of chromatin and protect bivalent promoters from hypermethylation, the direct effect of 5hmCs on gene transcription is unknown. In this present study, we have engineered a zinc-finger protein-based P16-specific DNA dioxygenase (P16-TET) to induce P16 hydroxymethylation and demethylation in cancer cells. Our results demonstrate, for the first time, that although the hydroxymethylated P16 alleles retain transcriptionally inactive, hydroxymethylation could increase the susceptibility of reactivation of methylated P16 alleles.

A review of head and neck cancer staging system in the TNM classification of malignant tumors (eighth edition).

A number of major modifications were made to the classification of head and neck carcinomas in the eighth edition of the American Joint Committee on Cancer, Cancer Staging Manual and Union for International Cancer Control TNM classification of Malignant Tumors. These modifications were aimed at improving the prognosis prediction accuracy of the system. In this article, we review the new edition of the TNM classification system. Among the several changes in the new system, a separate algorithm for p16-positive oropharyngeal carcinoma was included, as were new chapters on 'Head and Neck Skin Carcinoma' and 'Unknown Primary Carcinoma-Cervical Nodes.' Changes to Tumor (T) classification were made by introducing the depth of invasion of oral carcinoma, whereas changes to Node (N) classification were made by adding extra-nodal extension. It is believed that these changes will help improve the accuracy of the system in the prediction of prognosis. However, it is necessary to verify their validity through further clinical research.

Long-term analysis of transorally resected p16 + Oropharynx cancer: Outcomes and prognostic factors.

OBJECTIVE: We observed high survival in a previous report of a p16-positive, oropharyngeal carcinoma (OPC) cohort treated primarily with transoral laser microsurgery (TLM) ± adjuvant therapy and followed for ≥ 12 months. To address long-term outcomes of primary transoral surgery for this unique disease, we present an updated analysis of our cohort with extended follow-up. METHODS: A prospectively assembled TLM cohort of 171 OPC patients was analyzed for disease-free, disease-specific, and overall survival (disease-free survival [DFS], disease-specific survival [DSS], overall survival [OS]) and functional outcomes, with a minimum follow-up of 60 months or to death. RESULTS: Median follow-up was 103 (60-201) months. Five-year DFS, DSS, and OS estimates were 85% (95% confidence interval [CI]: 80%-91%), 93% (95% CI: 89%-97%), and 90% (95% CI: 86%-95%). Recurrence occurred in 20 (12%; 7 locoregional, 13 distant); median time to recurrence was 18.8 months; and 90% occurred within 48 months. Age, smoking, American Joint Committee on Cancer 8th edition clinical tumor-category, pathologic tumor (pT)-category, pathologic tumor-node-metastasis (pTNM), and any adjuvant were significantly associated with disease-free survival in multivariable analyses, whereas pT-category, pN-category, TNM grouping, and angioinvasion were associated with DSS. A second primary developed in six (3.5%) patients. Indications for gastrostomy were recurrence/second primary (11), postadjuvant esophageal stenosis (6), comorbidities (3), and osteo/chondroradionecrosis (3); only seven (4%) had a gastrostomy tube in the absence of these factors, all of whom received adjuvant therapy. Two had a tracheostomy tube [chondoradionecrosis (1), recurrence (1)]. CONCLUSION: High 5-year survival and locoregional control were observed, with recurrence occurring more commonly as distant metastasis. The observed time to recurrence suggests posttreatment oncologic surveillance for at least 48 months. Identified prognosticators will inform adjuvant treatment considerations, trial planning, and patient counseling for long-term outcomes. Laryngoscope, 2018 LEVEL OF EVIDENCE: 2b Laryngoscope, 129:1141-1149, 2019.

Histone Deacetylation in the Promoter of p16 Is Involved in Fluoride-Induced Human Osteoblast Activation via the Inhibition of Sp1 Binding.

Chronic fluorosis is a systemic condition which principally manifests as defects in the skeleton and teeth. Skeletal fluorosis is characterized by aberrant proliferation and activation of osteoblasts, however, the underlying mechanisms of osteoblast activation induced by fluoride are not fully understood. Therefore, we investigated the pathogenic mechanism of human primary osteoblast proliferation and activation in relation to histone acetylation of the promoter p16, a well-known cell cycle regulation-related gene. The results showed that sodium fluoride (NaF) induced deacetylation and decreased expression of the p16 gene via inhibition of specificity protein 1 (Sp1) binding to its response element, which accounts for NaF increasing cell viability and promoting proliferation in human primary osteoblasts. These results reveal the regulatory mechanism of histone acetylation of the p16 gene on osteoblast activation in skeletal fluorosis.

Aberrant methylation-induced dysfunction of p16 is associated with osteoblast activation caused by fluoride.

Chronic exposure to fluoride continues to be a public health problem worldwide, affecting thousands of people. Fluoride can cause abnormal proliferation and activation of osteoblast and osteoclast, leading to skeletal fluorosis that can cause pain and harm to joints and bones and even lead to permanent disability. Nevertheless, there is no recognized mechanism to explain the bone lesions of fluorosis. In this work, we performed a population study and in vitro experiments to investigate the pathogenic mechanism of skeletal fluorosis in relation to methylation of the promoter of p16. The protein coded by the p16 gene inhibits cdk (cyclin-dependent kinase) 4/cdk6-mediated phosphorylation4 of retinoblastoma gene product and induces cell cycle arrest. The results showed that hypermethylation of p16 and reduced gene expression was evident in peripheral blood mononuclear cells of patients with fluorosis and correlated with the level of fluoride exposure. Studies with cell cultures of osteoblasts revealed in response to sodium fluoride (NaF) treatment, there was an induction of p16 hypermethylation and decreased expression, leading to increased cell proliferation, a longer S-phase of the cell cycle, and development of skeletal fluorosis. Further, the methylation inhibitor, 5-aza-2-deoxycytidine, reversed the p16 hypermethylation and expression in response to NaF. These results reveal a regulatory role of p16 gene methylation on osteoblasts activation during the development of skeletal fluorosis.

Promoter DNA Methylation and mRNA Expression Level of p16 Gene in Oral Squamous Cell Carcinoma: Correlation with Clinicopathological Characteristics.

The aim of this study was to investigate the relationship between p16 methylation and its expression in oral squamous cell carcinoma (OSCC). Also the contribution of clinicopathological factors, HPV infection and smoking in p16 expression and promoter methylation has been investigated. In this study 67 consecutive OSCC patients and 59 normal individuals were enrolled. All patients were candidates for surgery of oral cavity and fresh tumor biopsies were collected and processed for DNA and RNA extraction. Normal gingival tissues were collected from individuals referred to dentistry clinic and considered as controls. All the cases and controls were checked for HPV infection and then promoter methylation and expression of p16 gene were determined using Methylation-specific PCR (MSP) and real-time PCR (QPCR), respectively. Methylation of p16 in tumors and normal tissues were 59.7 and 38.9%, respectively. Most of hypermethylated samples (>82%) were in high grades. P16 methylation was comparable in HPV+ and HPV- patients or smokers. P16 was overexpressed (~3 fold; p = 0.044) in HPV+ tumors, but it was significantly down-regulated in smoker patients (40% of all tumors). Comparison of P16 expression in OSCC tumors with different degrees of promoter methylation further suggest the relationship of methylation rate and down-regulation of P16 expression. The p16 methylation and expression was differentially affected in patients with HPV infection and the smoker cases. Regardless of the influence of environmental factors, it appears that P16 status is useful for classifying patients with OSCC and for influencing treatment strategies in accordance with this classification. Moreover, targeting the upregulation of p16 could be a promising therapeutic option.

Survival for HPV-positive oropharyngeal squamous cell carcinoma with surgical versus non-surgical treatment approach: A systematic review and meta-analysis.

The optimal management of human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) with primary surgical versus non-surgical treatment is unclear. The objective of this systematic review was to evaluate the literature and compare survival for primary surgical versus non-surgical treatment of HPV-positive OPSCC. We performed a comprehensive literature search of multiple electronic databases for relevant articles up to February, 2017. Studies reporting mortality or hazard ratio (HR) for overall survival (OS) in primary HPV-positive OPSCC patients were eligible. Seventy-three articles were eligible, of which 66 included single-modality (19 surgical, 47 non-surgical), and 7 included both surgical and non-surgical modalities. There were no randomized studies comparing outcomes between both modalities. In a meta-analysis of both-modality studies, OS with surgical treatment was not significantly different from non-surgical treatment (pooled HR 1.12; 95% CI: 0.35, 3.57). There was significant heterogeneity between studies (I2 = 82.4%). Among single-modality studies, the mortality rate was lower with surgical [pooled proportion 0.15 (95% CI: 0.09, 0.21)] versus non-surgical treatment [0.20 (95% CI:0.15, 0.24)]. In a subgroup analysis, OS was higher for HPV-positive versus HPV-negative OPSCC, irrespective of the treatment modality. We conclude that there is an absence of high-quality studies that compare survival for HPV-positive OPSCC treated with primary surgical versus non-surgical approach. The available data suggest no statistical or clinically meaningful difference in survival between the two approaches. HPV-positivity was a key prognostic factor irrespective of treatment modality. Further high-quality studies with consistent data reporting are needed to inform the choice for optimal treatment modality for HPV-positive OPSCC.

The hypermethylation of p16 gene exon 1 and exon 2: potential biomarkers for colorectal cancer and are associated with cancer pathological staging.

BACKGROUND: Tumor suppressor gene p16 promoter hypermethylation has been widely studied in colorectal cancer (CRC), yet its clinicopathological significance remains controversial. The methylation alterations of other regions within p16 gene are still rarely researched. The present study aimed to explore the methylation changes of p16 gene body in CRC and to find whether they were associated with clinicopathological staging of CRC. METHODS: Paired colorectal cancer tissues and corresponding adjacent normal tissues from 30 CRC patients were collected. The methylation levels of two CpG islands within p16 gene body, exon 1 and exon 2, were accurately assessed simultaneously by a LC-MS/MS method. The p16 protein expressions were assessed by immunohistochemistry assay. Statistical analyses were carried out using SPSS 17.0 software. Heat-map analysis was carried out by HemI 1.0 software. RESULTS: In the present study, CRC tissues showed more highly methylated than adjacent normal tissues at both CpG islands of p16 gene. And exon 2 hypermethylation was higher and more frequent than exon 1. The ROC curve analysis showed that the simultaneous use of both indicators had excellent sensitivity and specificity for distinguishing CRC tissues and adjacent normal tissues. Following, the methylation level of p16 exon 1/2 was negatively related to p16 protein expression. Further correlation analysis revealed that p16 exon 1 hypermethylation was associated with N/Dukes staging (p = 0.033), and p16 exon 2 hypermethylaiton was associated with T staging (p = 0.035). CONCLUSIONS: The p16 gene body was remarkably hyper-methylated in CRC tissues and associated with p16 protein expression and cancer clinicopathological staging. The combination of p16 exon 1 and exon 2 could better reflect the overall methylation status of p16 gene body and provide potential biomarkers of CRC.

The innovative regularity and role of p16 methylation in blood during HCC development.

Purpose: This study was performed to examine the regularity and role of p16 methylation in hepatocellular carcinoma (HCC) blood. Methods: Big data of the case-control studies due to blood p16 methylation detection were collected in English and Chinese Journals. The risk of HCC's histologic process was investigated using both Meta-analysis and the quantitative correlation analysis. Results: p16 methylation frequencies in blood were gradually increased from 0 % in normal to 10 % in benign disease, and to 60 % in HCC development. Based on p16 methylation of normal control blood, p16 methylation between normal and benign disease had no risk, and the methylation risk in HCC was significantly increased from normal to HCC through benign disease OR, 95% CI =16.23 ( 11.66, 22.58 ). Compared with the benign disease matched by HCC patient, the methylation risk of p16 in HCC was found, with the pooled OR value of 10.06 (95% IC = 7.64, 13.21) in blood. In addition, the regulatory mechanism affecting p16 methylation risk in normal blood had no role, and the strength of p16 methylation risk was rapidly increased between benign diseases and HCC blood. p16 methylation risk started from the patients with benign disease in blood. These results in blood and tissue detection were basically consistent. Conclusions: HCC pathogenesis affecting p16 methylation don't work during normal blood, when from benign diseases to HCC bloods, can produce powerful role. The transcriptional inactivation associated with p16 methylation might start from benign liver disease, and might be increased from benign liver disease to HCC process. p16 methylation in blood can be used as a promising non-invasive biomarker to HCC's prediction and diagnosis.

Double signal enhancement strategy based on rolling circle amplification and photoinduced electron transfer for ultrasensitive fluorometric detection of methylated DNA.

The authors describe a novel assay for the detection of methylated DNA site. Rolling circle amplification and CdSe/ZnS quantum dots with high fluorescence efficiency are applied in this method. The CdSe/ZnS quantum dots act as electron donors, and hemin and oxygen (derived from hydrogen peroxide act as acceptors in photoinduced electron transfer. The assay, best performed at excitation/emission peaks of 450/620 nm, is sensitive and specific. Fluorometric response is linear in the 1 pM to 100 nM DNA concentration range, and the lowest detectable concentration of methylated DNA is 142 fM (S/N = 3). The method is capable of recognizing 0.01% methylated DNA in a mixture of methylated/unmethylated DNA. Graphical abstract A novel method for methylated sites detection in DNA is established. Rolling circle amplification and photoinduced electron transfer. CdSe/ZnS quantum dots with high fluorescence efficiency act as the electron donor, while G-quadruplex/hemin and hydrogen peroxide derived oxygen act as electron acceptor. It presents a linear response towards 1 pM to 100 nM methylated DNA with a correlation coefficient of 0.9968, and the lowest detectable concentration of methylated DNA was 142 fM, with selectivity significantly superior to other methods.

Detection of p16 Promoter Hypermethylation by Methylation-Specific PCR.

DNA methylation plays a decisive role in the regulation and control of gene expression. DNA methylation is a covalent modification, in which a methyl group is attached to the 5th carbon of the cytosine ring of a CpG dinucleotide that is located upstream from the promoter region of a gene. Promoter hypermethylation (gain of DNA methylation) of the p16 gene may cause silencing of gene expression and plays an important role in cancer. Therefore, detection of the methylation status of p16 gene is an important tool in epigenetic studies of various human cancers. The methylation-specific PCR (MSP) is the most commonly used technique for studying DNA methylation. This technique is based on bisulfite modification of DNA, which converts unmethylated cytosine (C) into uracil (U) and leaving methylated cytosine (Cm) unchanged. Here we describe the bisulfite modification of DNA samples and detection of promoter methylation of p16 gene from bisulfite-treated DNA using MSP. In MSP, modified DNA samples are subjected to PCR amplification using methylated and unmethylated specific primers for the p16 gene separately. The PCR amplified products are then analyzed in a 2.5-3% agarose gel containing ethidium bromide. The PCR amplified band generated by specific sets of primers is used to determine the methylation status of the p16 gene.

The effect of p53mut,P53wt and p16 on the expression of Smad4 in lung cancer H1299 cells / 临床外科杂志

Objective To investigate the influence of exogenous p53mut, p53wt and p16 on the expression of Smad4 in lung cancer H1299 cells. Methods Target genes (p53mut, p53wtand p16) were amplified by PCR and inserted into effective eukaryotic expression vector pIRES2-EGFP, respectively. These recombinant plasmids were transfected into H1299 cells by lipofectamine. The fluorescence microscope was employed to observe the transfected cells and the expression of EGFP. RT-PCR was used to validate the transfection efficiency. Western blot assay was used to detect the change of the Smad4 expression in H1299, Results Green fluorescence was observed under fluorescence microscope in the transfected H1299 cells at 72 hour post transfection. RT-PCR indicated that p53mut, p53wt and p16 genes were highly expressed in H1299 cell. There was no significant difference in Samd4 expression between the empty plasmid group and control group(P＞0.05). But the expression of Samd4 in p53mut transfected group was decreased(P＜0.05). On the contrary, the expression of Smad4 was increased in the p53wt transfected group and P53wt and p16 co-transfected group. Moreover, the increase was more obvious in the P53wt and p16 cotransfected group(P＜ 0.05). Conclusion P53mut gene transfection reduces the expression of Smad4 and P53wt. The co-infection of p53mut and p16 increases the expression of Smad4 in the H1299 cells. The tumor promoting effect of p53mut and the antitumor effect of p53

Low-dose decitabine enhances chidamide-induced apoptosis in adult acute lymphoblast leukemia, especially for p16-deleted patients through DNA damage.

AIM: To investigate the combined action of decitabine (DAC) with chidamide (CS055) on acute lymphoblastic leukemia (ALL) cells. MATERIALS & METHODS: ALL cell lines as well as primary cells from 17 ALL patients were subjected to different treatments and thereafter cell counting Kit-8 (CCK-8) assay, flow cytometry and western blot were employed to determine IC50, apoptosis and checkpoint kinase 1 and γH2A.X expression. RESULTS: Low-dose DAC combined with CS055 could effectively kill ALL cells by the reduction of cell viability and induction of apoptosis. This was also observed in primary cells from 17 ALL patients, especially for those with p16 gene deletion. Suppression of checkpoint kinase 1 phosphorylation and upregulation of γH2A.X expression was demonstrated to participate in DAC plus CS055-induced apoptosis. CONCLUSION: Low-dose DAC could enhance chidamide-induced apoptosis in adult ALL, especially for patients with p16 gene deletion through DNA damage.

p16 gene silencing along with p53 single-nucleotide polymorphism and risk of esophageal cancer in Northeast India.

The high incidence of esophageal cancer in Northeast India and the unique ethnic background and dietary habits provide a great opportunity to study the molecular genetics behind esophageal squamous cell carcinoma in this part of the region. We hypothesized that in addition to currently known environmental risk factors for esophageal cancer, genetic and epigenetic factors are also involved in esophageal carcinogenesis in Northeast India. Therefore, in this study, we explored the possible association between the two important G1 cell cycle regulatory genes p16 and p53 and environmental risk factors and risk of esophageal carcinogenesis. A total of 100 newly diagnosed esophageal cancer cases along with equal number of age-, sex-, and ethnicity-matched controls were included in this study. Methylation-specific polymerase chain reaction was used to determine the p16 promoter methylation status. Single-nucleotide polymorphism at codon 72 of p53 gene was assessed by the polymerase chain reaction-restriction fragment length polymorphism method. Aberrant methylation of p16 gene was seen in 81% of esophageal cancer cases. Hypermethylation of p16 gene was not found in healthy controls. p53 Pro/Pro genotype was found to be a risk genotype in Northeast India compared with Arg/Pro and Arg/Arg. p53 variant/polymorphism was significantly associated with esophageal cancer risk in the study population under all three genetic models, namely, dominant model (Arg/Pro + Pro/Pro vs Arg/Arg odds ratio = 2.25, confidence interval = 1.19-4.26; p = 0.012), recessive model (Arg/Arg + Arg/Pro vs Pro/Pro odds ratio = 2.35, confidence interval = 1.24-4.44; p = 0.008), and homozygous model (Pro/Pro vs Arg/Arg odds ratio = 3.33, confidence interval = 1.54-7.20; p = 0.002). However, p53 variant/polymorphism was not statistically associated with esophageal cancer risk under the heterozygous model (Pro/Pro vs Arg/Pro). In the case-only analysis based on p16 methylation, the p53 variant/polymorphism (Pro/Pro or Arg/Pro) showed significant association for esophageal cancer risk (odds ratio = 3.33, confidence interval = 1.54-7.20; p = 0.002). Gene-gene and gene-environment interaction using the case-only approach revealed a strong association between p16 methylation, p53 single-nucleotide polymorphism, and environmental factors and esophageal cancer risk. Cases with p16 methylation and p53 variant/polymorphism (Pro/Pro or Arg/Pro) along with both betel quid and tobacco chewing habit (odds ratio = 8.29, confidence interval = 1.14-60.23; p = 0.037) conferred eightfold increased risk toward esophageal cancer development. This study reveals a synergistic interaction between epigenetic, genetic, and environmental factors and risk of esophageal cancer in this high-incidence region of Northeast India. The inactivation of either p16 or p53 in a majority of esophageal cancer cases in this study suggests the possible crosstalk between the important cell cycle genes.

The synergic effect of HPV infection and epigenetic anomaly of the p16 gene in the development of cervical cancer.

BACKGROUND: Cervical cancer is the most common cancer in Indian women. Infection with a high-risk human papillomavirus (HR-HPV) is the greatest risk factor for developing cervical cancer. The genetic and epigenetic changes in the tumor suppressor p16 gene is play an important role in the development of cervical cancer. OBJECTIVE: To evaluate the expression and promoter methylation of p16 gene in HR-HPV infected squamous cell carcinoma of the uterine cervix. METHODS: To find out p16INK4a expression and methylation status 105 squamous cell carcinoma of the uterine cervix were investigated by using immunohistochemistry and Methylation Specific PCR techniques. RESULTS: HPV16/18 was amplified in 83.8% cases of the cervix. 80% of them were positive for HPV type 16, while only 3.8% were positive for HPV type 18. Promoter CpG island hypermethylation of p16 gene was detected in 20.9% tissue samples of cervical carcinoma. Of these hypermethylated samples 90.9% cases showed nil/very low p16INK4a expression (P= 0.001). Overexpression of p16INK4a was observed in 73.3% cases of HR-HPV infected squamous cell carcinoma of the cervix. CONCLUSION: An association between p16 methylation, expression, and HR-HPV infection suggested the compliance of HPV infection and aberration of p16 gene have a synergic effect on initiation and progression of cervical carcinoma.

[Clinical analysis of adult Philadelphia chromosome-positive acute lymphoblastic leukemia with p16 gene deletion].

Objective: To investigate the clinical implications of p16 gene deletion in adult Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) . Methods: Retrospective analysis of clinical, immunophenotypic, cytogenetics, molecular characteristics and prognosis of 80 newly diagnosed Ph(+) ALL patients with p16 deletion. Results: Of 80 adult Ph(+) ALL, the prevalence of p16 gene deletion was 31.3%. p16 gene deletion carriers frequently accompanied with high WBC counts (WBC≥30×10(9)/L) and CD20 expression. The incidence of complex chromosome abnormality in p16 gene deletion group was higher than that in non-deletion group, with alternations in chromosome 7, 8, 19 and der (22) more frequently observed. There was no difference occurred between patients with or without p16 gene deletion in complete remission (CR) rate following induction chemotherapy combined with tyrosine kinase inhibitors (TKIs) . However, after three cycles of chemotherapy, the MMR and CMR rate in the p16 gene deletion group was lower than patients with wild-type p16 gene (P=0.034, P=0.036) . The p16 gene deletion patients showed no significant differences in MMR, CMR and relapse rate between Imatinib or Dasatinib plus chemotherapy (P>0.05) . Deletion of p16 gene was significantly associated with poor outcomes including worse overall survival (OS) (37.1% vs 54.1%, P=0.037) , lower disease free-survival (DFS) (12.4% vs 45.9%, P=0.026) , and increased cumulative incidence of relapse (P=0.033) . Among the 25 patients with p16 deletion, 14 underwent allo-HSCT and the median survival was 21 months, better than that of patients received chemotherapy alone (12 months) (P=0.030) . Conclusion: This study indicated that deletion of p16 was associated with poor prognosis in adult Ph(+) ALL, and the utility of second-generation TKI (Dasatinib) does not necessarily have an edge on efficacy over Imatinib, but allo-HSCT has the potential of elongating life expectancy. It is an important significance to define the status of p16 in Ph(+) ALL for predicting prognosis and guiding therapy decision-making.