Aberrant methylation of p14(ARF), p15(INK4b) and p16(INK4a) genes and location of the primary site in pulmonary squamous cell carcinoma

Aberrant methylation of cytosines in CpG islands of the promoter regions of tumor suppressor genes is found in human tumors as a common mechanism of gene silencing. We investigated the methylation status of the chromosome 9p21 gene cluster (p14(ARF), p15(INK4b) and p16(INK4a) genes) by methylation-specific polymerase chain reaction in 20 central and 40 peripheral types of pulmonary squamous cell carcinoma (SqCC) in order to determine the differences between the pathogeneses of the central and peripheral types of SqCC. The frequencies of methylation were 30% for the p14(ARF) gene, 20% for the p15(INK4b) gene and 40% for the p16(INK4a) gene in the central type and 25% for the p14(ARF) gene, 10% for the p15(INK4b) gene and 38% for the p16(INK4a) gene in the peripheral type. Cases in which there was methylation of the p16(INK4a) gene had a higher smoking index in the peripheral type (P = 0.007). This trend was not detected in the central type. Methylation of two or three genes was observed in 55% of methylation in at least one gene of the central type but in only 17% of the peripheral type. This overlap methylation of the chromosome 9p21 gene cluster was found more frequently in the central type (P = 0.02). These findings suggest one of the epigenetic differences between the central and peripheral types of SqCC.     

Immunohistochemical inactivation of p14ARF concomitant with MDM2 overexpression inversely correlates with p53 overexpression in oral squamous cell carcinoma

The CDKN2 gene encodes two structurally different proteins: a cyclin-dependent kinase inhibitor called p16, which regulates retinoblastoma protein (pRb)-dependent G1 arrest, and a cell cycle inhibitor designated p14ARF, which arrests cell growth in G1-S and also in G2-M. Whereas inactivation of p16 has been described as a frequent event in various cancers, including oral cancer, the current function of p14ARF is still poorly understood. A physical association between p14ARF and MDM2 blocks MDM2-induced p53 degradation, resulting in increased levels of p53, which in turn leads to cell cycle arrest. The present study immunohistochemically examined the expression of p16 and p14ARF together with pRb, MDM2 and p53 status in a series of oral cancers. The results showed that p14ARF was frequently absent in the oral cancers (15/37, 41%) as was p16 immunostaining. Concomitant immunopositivity for p14ARF and MDM2 overexpression was frequently observed in a subset of the cancers, whereas an inverse correlation between p14ARF and MDM2 expression and the diffuse staining of p53 was clearly detected. Moreover, the results showed that in most cases of oral cancer (35/37, 95%) at least one protein was altered, and lymph node metastasis was more frequent in the tumors with alterations in both the p16/pRb and p14ARF/p53 pathway (8/16, 50%) than in the tumors with one or no alteration of these two major pathways.     

The retinoblastoma protein/p16 INK4A pathway but not p53 is disrupted by human papillomavirus in penile squamous cell carcinoma

Stankiewicz E, Prowse D M, Ktori E, Cuzick J, Ambroisine L, Zhang X, Kudahetti S, Watkin N, Corbishley C & Berney D M
(2011) Histopathology 58 , 433–439
The retinoblastoma protein/p16 ^INK4A pathway but not p53 is disrupted by human papillomavirus in penile squamous cell carcinoma Aims: The pathogenesis of penile squamous cell carcinoma (PSCC) is not well understood. Human papillomavirus (HPV) may be involved in carcinogenesis, but few studies have compared cell‐cycle protein expression in HPV positive and negative cancers. The aim was to determine the extent of HPV infection in different histological subtypes of PSCC and its impact on the expression of key cell‐cycle proteins: p53, p21, p16^INK4A and retinoblastoma (RB) protein. Methods and results: One hundred and forty‐eight PSCC samples were examined immunohistochemically for RB, p16^INK4A, p53 and p21 protein expression. One hundred and two cases were typed for HPV by PCR. HPV DNA was detected in 56% of tumours, with HPV16 present in 81%. Basaloid tumours were related strongly to HPV infection (10 of 13), while verrucous were not (three of 13). Fifty‐nine per cent (38 of 64) of usual type SCCs had HPV infection. RB protein correlated negatively (P < 0.0001) and p16^INK4A (P < 0.0001) and p21 (P = 0.0002) correlated positively with HPV infection. p53 did not correlate with HPV infection. Conclusions: HPV infection is present in more than half of penile cancers and it is responsible for RB pathway disruption. However, no link between HPV and p53 immunodetection was found. Only basaloid and half of usual‐type PSSCs correlate with HPV infection, confirming possible separate aetiologies for those tumours.     

Primary squamous cell carcinoma of the vagina: human papillomavirus detection, p16(INK4A) overexpression and clinicopathological correlations

Fuste V, del Pino M, Perez A, Garcia A, Torne A, Pahisa J & Ordi J
(2010) Histopathology 57, 907–916 Primary squamous cell carcinoma of the vagina: human papillomavirus detection, p16 ^INK4A overexpression and clinicopathological correlations Aim: To determine the role of human papillomavirus (HPV) in the pathogenesis of primary squamous cell carcinoma of the vagina (SCCVa), and to evaluate its clinicopathological significance. Methods and results: All cases of SCCVa diagnosed over a 15‐year period from two hospitals in Barcelona, Spain (n = 32) were retrieved. Patients with a history of carcinoma of the cervix diagnosed <5 years before were excluded. HPV was detected and typed by polymerase chain reaction (PCR) using SPF10 primers. Immunohistochemistry was performed for p16 and p53. HPV was detected in 25 cases (78.1%). HPV16 was the most prevalent type. Patients with HPV‐positive tumours were associated frequently with a history of carcinoma or intraepithelial neoplasia of the cervix or vulva diagnosed more than 5 years before (56% versus 0%; P = 0.01). HPV‐positive tumours were more frequently of non‐keratinizing, basaloid or warty type than HPV‐negative neoplasms (84% versus 14.3%; P < 0.001), and showed diffuse positive immunoreactivity for p16^INK4a (96%, versus 14.3%; P < 0.001). The sensitivity and specificity of p16 to identify HPV‐positive tumours were 96% and 85.7%, respectively. Conclusions: A high number of SCCVs are related to HPV infection and may be identified by immunohistochemistry for p16. HPV‐positive tumours tend to affect women with history of cervical neoplasia.     

Frequent alteration of p16(INK4a)/p14(ARF) and p53 pathways in the round cell component of myxoid/round cell liposarcoma: p53 gene alterations and reduced p14(ARF) expression both correlate with poor prognosis

In myxoid/round cell liposarcoma (MLS/RCLS), the presence of a round cell (RC) component has been reported to correlate with a worse prognosis for the patients. However, little is known about the molecular genetic differences between conventional myxoid (MX) components and RC components in this tumour. The aim of this study was to investigate the possible implications of molecular alterations of G1 to S-phase check-point genes, especially in the RC component. We evaluated the immunohistochemical expression of p53, MDM2, p14 and p16 protein and assessed proliferative activities using MIB-1 in 29 RC components and 81 MX components from 90 cases. Mutation of the p53 gene, amplification of the MDM2 gene, homozygous deletion, methylation status and mutation of the p16(INK4a)/p14(ARF) genes were also investigated, using concordant paraffin-embedded and frozen material. The data were analysed together with clinicopathological factors to assess their prognostic implications in MLS/RCLS. Immunohistochemically, the over-expression of p53 protein (p = 0.01366) and the reduced expression of p14 (p < 0.0001) and p16 (p < 0.0001) proteins were significantly more frequently observed in RC components than in MX components. Reduced expression of p14 protein correlated significantly with hypermethylation of the p14(ARF) gene promoter (p = 0.0176) and over-expression of p53 protein (p = 0.00837). By univariate analysis, reduced expression of p14 and p53 missense mutation were found to reduce the rate of survival significantly (p < 0.05). Multivariate analysis, including clinicopathological factors, revealed that tumour site (p = 0.0251), the presence of an RC component (p = 0.0113), high MIB-1 labelling index (p = 0.0005) and p53 missense mutation (p = 0.0036) were adverse prognostic factors. In MLS/RCLS, reduction of p14 protein expression and p53 mutation were related to poor prognosis. Accordingly, the p14(ARF)/p53 pathway may contribute to the presence of an RC component and malignant progression in this tumour.     

Expression of p53 protein in laryngeal squamous cell carcinoma and dysplasia: possible correlation with human papillomavirus infection and clinicopathological findings

In order to evaluate the expression of p53 protein in 28 premalignant and 40 malignant squamous cell proliferations of the larynx and its relationship to tobacco consumption, human papillomavirus infection and differentiation grade of the lesions, p53 expression was examined by means of a microwave post-fixation immunohistochemical method using the PAb 240 and PAb 1801 monoclonal antibodies. HPV infection was assessed by non-isotopic in situ hybridization (NISH) and polymerase chain reaction (PCR). A large proportion of carcinomas (77.5%) and dysplasias (61%) expressed p53. No difference was found between differentiation grades of the lesions regarding p53 detection (P>0.1), but moderate or intense p53 expression was more frequent in the carcinomas (P<0.05). A statistical correlation was found between cigarette consumption and both p53 detection and p53 staining intensity (P<0.05 in each case). HPV study revealed HPV 16 and 18 infection only in carcinomas. The frequency was 28% and the physical state of the virus as demonstrated by NISH was integration into the genome. We observed an inverse relationship between HPV infection and p53 expression (P=0.006). Our findings suggest that p53 overexpression is a common and early event which increases in frequency with progression of laryngeal squamous cell carcinoma. The expression of p53 is influenced by tobacco and high-risk types of HPV.     

Expression of cell cycle-regulatory proteins, MIB-1, p16, p53, and p63, in squamous cell carcinoma of conjunctiva: not associated with human papillomavirus infection

Squamous cell carcinoma (SCC), the most common primary malignant tumor of the conjunctiva, has a variable clinical presentation and immunohistochemical profile. Abundant cell cycles exist, including MIB-1 (Ki67 antigen), p16, p53, and p63, within the conjunctiva SCC. This investigation first reports the expressions of cell cycle markers in SCC. A retrospective study was conducted between December 1976 and June 2004, comprising 13 consecutive patients with conjunctiva SCC who were treated with surgical excision. Detailed clinical parameters were also reviewed. Overexpression of MIB-1, p16, p53, and p63 genes were studied by immunohistochemistry. Genechip containing 39 subtypes was used to elucidate human papillomavirus (HPV). The study group contained 13 (100%) men, with a mean age of 68±18 years and follow-up period of 20±17 months. The sample included four (33%) SCC located in the left eye and two (17%) recurrent SCC. Overexpression of the p53 and p63 was considerably higher than that of the p16 (P<0.01). HPV DNA was not detected in any of the 13 cases. This work first examined the immunohistochemical overexpression of cell cycle (MIB-1, p16, p53, and p63) in SCC. This investigation then showed that the expression of cell cycles in SCC was associated with key tumor clinicopathological features. This approach can help distinguish the potential roles of cell cycle in the development of SCC.     

Overexpression of CyclinD1 and underexpression of p16 correlate with lymph node metastases in laryngeal squamous cell carcinoma in Chinese patients

Background CyclinD1 and p16 are involved in the regulation of G1 checkpoint and may play an important role in the tumorgenesis of laryngeal squamous cell carcinoma (LSCC). Previous studies have examined the level of expression of cyclinD1 or p16 in LSCC but no such information is available for their relation and their correlation with lymph node metastasis in Chinese patients. Patients and methods A total of 58 patients underwent surgical resection of laryngeal tumours in the Department of Otolaryngology, Qilu Hospital Shandong University between January 2001 and December 2002. All pathologic specimens were available for immunohistochemical study using antibodies against cyclinD1 and p16. Results Compared with normal epithelium, expression of CyclinD1 in the LSCC was significantly higher (62.1% vs. 10.0%, P < 0.05), expression of p16 was significantly lower (48.3% vs. 90.0%, P < 0.05); CyclinD1 expression in LSCC was up-regulated in TNM classification (r _s = 0.409, P < 0.05) as well as with cervical lymph node metastases (r _s = 0.294, P < 0.05); p16 expression in LSCC was down-regulated with cervical lymph node metastases (r _s = −0.275, P < 0.05); negative significant correlation between p16 immunostaining and CyclinD1 was observed in LSCC (r _s = −0.331, P < 0.05). Conclusion There was a negative correlation between CyclinD1 expression and p16 expression in LSCC. The over-expression of CyclinD1 and the under-expression of p16 may play a significant role in the incidence and development of LSCC and may be important indicators for cervical lymph node metastases in Chinese patients of LSCC. Zhi-jie Fu and Zhi-yong Ma are contributed to this work equally.     

喉癌p16、p15基因纯合性缺失的研究

目的 研究p16、p15基因缺失状态与喉癌发生、发展的关系。方法 提取喉癌新鲜组织中基因组DNA，采用聚合酶链反应技术，分别对80例喉癌进行p16基因第2外显子（p16E2）和67例喉癌进行p15基因第2外显子(p15E2）纯合性缺失研究。结果 检测p16E2弛合性缺失率为12.5%(10/80)，p15E2纯合性缺失率为11.94%（8／67），p16E2、p15E2共同缺失率为5.97%（4／67）。结论 p16E2和p15E2纯合缺失以及二者共同缺失与喉癌发生有相关性，可能在喉癌发生及恶性进展中起一定作用。     

Uterine cervical squamous cell carcinoma without p16 (CDKN2A) expression: Heterogeneous causes of an unusual immunophenotype

Immunohistochemically p16 (CDKN2A)‐negative uterine cervical squamous cell carcinoma (SCC) is uncommon, and there are few reports about its pathological features. This study explored the causes of p16 negativity in such cases. We analyzed diagnostic tissue samples of five cases of p16‐negative cervical SCC among 107 patients who underwent hysterectomy at Kyoto University Hospital between January 2010 and December 2015. The samples were subjected to immunohistochemical staining, in situ hybridization and a genetic analysis. Two of five cases were positive for human papilloma virus (HPV) by genotyping. One was positive for HPV56 with promoter hypermethylation of CDKN2A and co‐existing Epstein–Barr virus infection. Another was positive for HPV6 categorized as low‐risk HPV with condylomatous morphology. Among the remaining three cases, one had amplification of the L1 gene of HPV with promoter hypermethylation of CDKN2A and TP53 mutation, and one of the other two HPV‐negative cases had a homozygous CDKN2A deletion, while the other was positive for p53 and CK7. p16‐negativity of cervical SCC is often associated with an unusual virus infection status and CDKN2A gene abnormality.     

Human papillomavirus infection is not associated with laryngeal squamous cell carcinoma in Taiwan

Background/PurposeTo examine whether the prevalence rate of human papillomavirus (HPV) infection in Taiwanese patients with primary laryngeal squamous cell carcinoma (LSCC) is different from that in those with a vocal polyp (VP) or vocal fold leukoplakia (VFL).MethodsThis prospective cohort study recruited 41 consecutive patients with primary LSCC and 27 and 20 patients with VP and VFL, respectively. The HPV L1 gene in surgical specimens was detected using polymerase chain reaction. High-risk HPV DNA in tissue microarray specimens was detected using in situ hybridization. Expression of p16^INK4a in tissue microarray specimens was determined through immunohistochemistry.ResultsThe prevalence of HPV L1 DNA in the LSCC group was equivalent to that in the VP and VFL groups (7.3% vs. 7.4% vs. 10.0%; P = 0.929; effect size = 0.20). High-risk HPV DNA detected using in situ hybridization was relatively rare in all groups (2.6% vs. 5.3% vs. 0.0%; P = 0.636; effect size = 0.81). The prevalence of p16^INK4a positivity was significantly lower in the LSCC group than in the VP and VFL groups (5.1% vs. 58.8% vs. 14.3%; P < 0.001). Multivariate analysis results revealed that age ≥65 years (adjusted odds ratio, 4.09; 95% confidence interval, 1.21–13.91; P = 0.024) and p16^INK4a positivity (adjusted odds ratio, 0.10; 95% confidence interval, 0.02–0.53; P = 0.006) were LSCC risk factors.ConclusionHPV infection is uncommon in Taiwanese patients with LSCC and seems not to be associated with an increased LSCC risk. Larger sample size is warranted for further study.     

Survivin expression is a negative prognostic marker in laryngeal squamous cell carcinoma and is associated with p53 accumulation

AIMS: To investigate survivin expression in laryngeal squamous cell carcinoma (LSCC), its prognostic significance and relation to p53 status. Survivin is an inhibitor of apoptosis protein that is overexpressed in cancer. It has been implicated in both prevention of apoptosis and cell cycle regulation. It has been suggested that wild-type p53 represses survivin expression. METHODS AND RESULTS: Expression of survivin and p53 was analysed in 68 archival biopsy specimens of LSCC by immunohistochemistry. Survivin was detected in 67 of 68 LSCC cases; the proportion of survivin-positive cells varied from 8.2% to 100%. It was localized in the nucleus and/or cytoplasm of tumour cells. Of LSCC cases, 31.8% were p53+. The number of survivin-positive cells was significantly higher in the p53+ group. A high level of survivin expression and a supraglottic site of the tumour were two independent adverse prognostic factors in LSCC. CONCLUSIONS: Survivin is expressed in a varying proportion of cells in virtually all cases of LSCC. A high level of its expression predicts poor survival. Loss of wild-type p53 is a possible mechanism of survivin up-regulation in LSCC.     

Overexpression of the oncostatin M receptor in cervical squamous cell carcinoma cells is associated with a pro-angiogenic phenotype and increased cell motility and invasiveness

Oncostatin M receptor (OSMR) shows frequent copy number gain and overexpression in advanced cervical squamous cell carcinoma (SCC). We used cell-based in vitro assays, RNA interference, and integrative gene expression profiling to investigate the functional significance of this observation. CaSki and SW756 were selected as representative cervical SCC cells that overexpressed OSMR, and ME180 and MS751 as cells that did not. The STAT-dependent pro-angiogenic factors VEGF-A and ID1 were rapidly induced by OSM in CaSki/SW756 but not in ME180/MS751. However, rapid induction did occur in MS751 following forced OSMR overexpression, while depleting OSMR in CaSki abrogated VEGF-A expression. Conditioned medium from both CaSki and SW756 stimulated endothelial tube formation in vitro, effects that were inhibited by depleting OSMR in the SCC cells. For both CaSki and SW756, migration in a wound healing assay and invasion through Matrigel were stimulated by OSM and consistently inhibited by OSMR depletion. The phenotype was rescued by transfection with OSMR containing a silent mutation that provided specific siRNA resistance. Overall, there was a positive correlation between OSMR levels and invasiveness. We used gene expression profiling to identify genes induced by OSM in CaSki/SW756 but not in ME180/MS751. The most prominent gene ontology category groups for the differentially expressed genes were cell motility/invasion, angiogenesis, signal transduction, and apoptosis. We also profiled 23 cervical SCC samples, identifying genes that were differentially expressed in cases with OSMR overexpression versus those without. Integration of the datasets identified 15 genes that showed consistent differential expression in association with OSMR levels in vitro and in vivo. We conclude that OSMR overexpression in cervical SCC cells provides increased sensitivity to OSM, which induces pro-malignant changes. OSMR is a potential prognostic and therapeutic target in cervical SCC. The genes that mediate OSM:OSMR effects will be valuable indicators of the effectiveness of antibody blockade in pre-clinical systems.     

p16 Immunoreactivity in unusual types of cervical adenocarcinoma does not reflect human papillomavirus infection

Houghton O, Jamison J, Wilson R, Carson J & McCluggage W G
(2010) Histopathology 57, 342–350
p16 Immunoreactivity in unusual types of cervical adenocarcinoma does not reflect human papillomavirus infection Aims: The association between human papillomavirus (HPV) and cervical carcinoma is well known, with HPV being identifiable in almost all cervical squamous carcinomas and most adenocarcinomas. However, the prevalence of HPV in unusual morphological types of cervical adenocarcinoma has not been investigated extensively. The aim was to determine HPV status in a series of primary cervical adenocarcinomas, enriched for unusual morphological types. The relationship between HPV and p16 immunoreactivity in these neoplasms was also investigated, as it is generally assumed that in cervical neoplasms diffuse p16 expression is predictive of the presence of high‐risk HPV. Methods and results: Sixty‐three cervical adenocarcinomas, comprising those of usual type (n = 43), minimal deviation type (n = 4), gastric type (n = 3), intestinal type (n = 3), mesonephric type (n = 3), clear cell type (n = 4), serous type (n = 2) and hepatoid type (n = 1) underwent linear array HPV genotyping and immunohistochemistry for p16. Overall, HPV was identified in 32 of 56 cases (57%) in which sufficient DNA was present for analysis. The most common HPV types were 16 and 18, with these being identified in 20 and 18 cases, respectively, either alone or in combination. Seventy‐eight per cent of usual‐type adenocarcinomas were HPV‐positive, as was the single serous carcinoma in which there was sufficient DNA for analysis. In contrast, all minimal deviation adenocarcinomas and those of gastric, intestinal, mesonephric and clear cell types were HPV‐negative, as was the single hepatoid carcinoma. All usual‐type adenocarcinomas exhibited p16 immunoreactivity (diffuse staining in all but one case), as did 11 of 20 of those of unusual morphological type (five focal, six diffuse). Conclusions: Most, but not all, cervical adenocarcinomas of usual type contain HPV, but those of unusual morphological type are almost always HPV‐negative. This has implications for the efficacy of HPV vaccination in the prevention of cervical adenocarcinoma. A significant proportion of cervical adenocarcinomas are p16‐positive in the absence of HPV, illustrating that in these neoplasms diffuse p16 immunoreactivity is not a reliable surrogate marker of the presence of high‐risk HPV.     

Oncostatin M receptor is a novel therapeutic target in cervical squamous cell carcinoma

Cervical carcinoma is the second most common cause of cancer deaths in women worldwide. Treatments have not changed for decades and survival rates for advanced disease remain low. An exciting new molecular target for the treatment of cervical squamous cell carcinoma (SCC), and possibly for SCCs at other anatomical sites, is the oncostatin M receptor (OSMR). This cell surface cytokine receptor is commonly copy number gained and overexpressed in advanced cervical SCC, changes that are associated with significantly worse clinical outcomes. OSMR overexpression in cervical SCC cells results in enhanced responsiveness to the major ligand oncostatin M (OSM), which induces several pro‐malignant effects, including a pro‐angiogenic phenotype and increased cell migration and invasiveness. OSMR is a strong candidate for antibody‐mediated inhibition, a strategy that has had a major impact on haematological malignancies and various solid tumours such as HER2‐positive breast cancers. © 2013 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Promoter methylations of p16INK4a and p14ARF genes in early and advanced gastric cancer. Correlations of the modes of their occurrence with histologic type

The INK4a/ARF locus encodes two cell cycle-regulatory proteins, p16^INK4a and p14^ARF. These share an exon using different reading frames, and act through Rb and p53 pathways. Recently, it has been found that silencing of p16^INK4a and p14^ARF expressions by aberrant methylation of the CpG islands in the promoter regions is an alternative mechanism that inactivates possible tumor suppressor functions in various tumors. To clarify the features of gastric cancers with promoter methylation of p16^INK4a and p14^ARF, we investigated the methylation status in gastric cancer cell lines and primary gastric cancers using methylation-specific PCR (MSP), and correlated the methylation status with microsatellite instability (MSI), DNA ploidy pattern, p53 immunohistochemistry, and various clinicopathologic factors, paying attention to the correlations with the histologic types. Of 10 cell lines studied, silencing of the expression of p16^INK4a and p14^ARF due to promoter methylation was detected by MSP and RT-PCR in six (60%) and two (20%) cell lines, respectively. p14^ARF silencing was detected only in cell lines derived from gastric cancer of the diffuse type, while p16^INK4a silencing was found in cell lines derived from both diffuse and intestinal types. In 59 primary gastric cancers, promoter methylation of p16^INK4a and p14^ARF was found in 10 (17%) and 14 (24%) of the tumors independently, there being an association with DNA diploidy, but not with p53 immunohistochemistry. p16^INK4a methylation was found irrespective of tumor stages and histology. Whereas p14^ARF methylation was found more frequently in intestinal type cancers in an early stage and in diffuse type cancers in an advanced stage, MSI tended to be related especially to p14^ARF methylation in cancers of the intestinal type. Thus, the significance of p14^ARF methylation differed between intestinal and diffuse types, while such a difference was not observed in p16^INK4a methylation.