A Southeast Asian collaborative Delphi consensus on surveying risk factors for head and neck cancer screening and prevention

The objective of this study was to determine high value questions for early detection and prevention of head and neck cancer by querying content experts on patient risk factors relevant to local communities in Southeast Asia (i.e., Vietnam, Laos, China, and Singapore). The Delphi method was employed using three rounds of asynchronous surveying which included participants among five different collaborating medical centers. 60 total survey items were assessed for consensus defined by a priori measures on the relative level of value of these questions for use in head and neck cancer screening. 77% of items reached a consensus and no items were concluded to be of low value despite differences in conclusions regarding relative importance. Survey items focused on patient demographic information and physical examination were examined across variables such as expert department affiliation, academic designation, and years of experience and found to be without statistically significant differences. However, with consensus items related to social risk factors, it was determined that participants who had 15 or more years of experience or identified as otolaryngologists rated these items at a relatively lower value than their peers with less experience (p < 0.0001, p = 0.0017) or outside the field of otolaryngology (p = 0.0101). This study explicitly identifies patient variables to consider in head and neck cancer screening that have not previously been comprehensively or methodically assessed in current literature. Increasing awareness of these risk factors may benefit the design and implementation of future head and neck cancer early detection and prevention programs in Southeast Asia and beyond as well as positively impact head and neck cancer outcomes.

Mutational Signatures in Mandibular Ameloblastoma Correlate with Smoking

Ameloblastoma is a rare tumor of odontogenic epithelium, the low incidence rate of which precludes statistical determination of its molecular characterizations. Despite recent genomic and transcriptomic profiling, the etiology of ameloblastomas remains poorly understood. Risk factors of ameloblastoma development are also largely unknown. Whole exome sequencing was performed on 11 mandibular ameloblastoma samples. We identified 2 convergent mutational signatures in ameloblastoma: 1) a signature found in multiple types of lung cancers with probable etiology of tobacco carcinogens (COSMIC signature 4) and 2) a signature present in gingivobuccal oral squamous cell carcinoma and correlated with tobacco-chewing habits (COSMIC signature 29). These mutational signatures highlight tobacco usage or related mutagens as one possible risk factor of ameloblastoma, since the association of BRAF mutations and smoking was demonstrated in multiple studies. In addition to BRAF hotspot mutations (V600E), we observed clear inter- and intratumor heterogeneities. Interestingly, prior to BRAF mutation, important genes regulating odontogenesis mutated (e.g., corepressor BCOR), possibly playing important roles in tumorigenesis. Furthermore, recurrent mutations in the CDC73 gene, the germline mutations of which predispose patients to the development of jaw tumors, were found in 2 patients, which may lead to recurrence if not targeted by therapeutic drugs. Our unbiased profiling of coding regions of ameloblastoma genomes provides insights to the possible etiology of mandibular ameloblastoma and highlights potential disease risk factors for screening and prevention, especially for Asian patients. Because of the limited sample size and incomplete habitual, dietary, and occupational data, a causal link between tobacco usage and ameloblastoma still requires further investigations.

Prognostic Performance of Current Stage III Oral Cancer Patients After Curative Intent Resection: Evidence to Support a Revision of the American Joint Committee on Cancer Staging System

BACKGROUND

The American Joint Committee on Cancer (AJCC) stage III classification of oral cavity squamous cell carcinoma (OCSCC) represents a heterogeneous group of patients with early local disease with regional metastases (T1N1 and T2N1) and advanced local disease with or without regional metastasis (T3N0 and T3N1).

OBJECTIVE

The aim of this study was to evaluate prognostic heterogeneity in the stage III category.

METHODS AND PATIENTS

An international retrospective multicenter study of 1815 patients who were treated for OCSCC from 2003 to 2011.

RESULTS

Kaplan-Meier survival analysis and multivariate models of stage III patients revealed better overall survival (OS; HR 2.12, 95 % CI 1.03-4.15; p = 0.01) and disease-specific survival (DSS; HR 1.7, 95 % CI 1.16-4.12; p = 0.04) rates for patients with T1-2N1/T3N0 disease than for patients with T3N1 disease. The outcomes of patients with T3N1 and stage IVa disease were similar (p = 0.89 and p = 0.78 for OS and DSS, respectively). Modifying stage classification by transferring the T3N1 category to the stage VIa group resulted in a better prognostic performance [Harrell's concordance index, C index 0.76; Akaike's Information Criterion (AIC) 4131.6] compared with the AJCC 7th edition staging system (C index 0.65; AIC 4144.9) for OS. When DSS was assessed, the suggested staging system remained the best performing model (C index 0.71; AIC 1061.3) compared with the current AJCC 7th edition staging (C index 0.64; AIC 1066.2).

CONCLUSIONS

The prognosis of T3N1 and stage IVa disease are similar in OCSCC, suggesting that these categories could be combined in future revisions of the nodal staging system to enhance prognostic accuracy.

Management of thyroid nodules and surgery for differentiated thyroid cancer

The incidence of well-differentiated thyroid cancer has seen a worldwide increase in the last three decades. Whether this is due to a 'true increase' in incidence or simply increased detection of otherwise subclinical disease remains unclear. The treatment of thyroid cancer revolves around appropriate surgical intervention, minimising complications and the use of adjuvant therapy in select circumstances. Prognostic features and risk stratification are crucial in determining the appropriate treatment. There continues to be considerable debate in several aspects of management in these patients. Level 1 evidence is lacking, and there are limited prospective data to direct therapy, hence limiting decision-making to retrospective analyses, treatment guidelines based on expert opinion and personal philosophies. This overview focuses on the major issues associated with the investigation of thyroid nodules and the extent of surgery. As overall survival in well-differentiated thyroid cancer exceeds 95%, it is important to reduce over-treating the large majority of patients, and focus limited resources on high-risk patients who require aggressive treatment and closer attention. The onus is on the physician to avoid treatment-related complications from thyroid surgery and to offer the most efficient and cost-effective therapeutic option.

Kruppel-like factor 5 modulates p53-independent apoptosis through Pim1 survival kinase in cancer cells

Although Kruppel-like factor 5 (KLF5) is a transcription factor that has been implicated in pathways critical to carcinogenesis, controversy persists as to whether it functions as a tumor suppressor or as an oncogene. Here, we describe a novel role for KLF5 in a p53-independent apoptotic pathway. Using RNA-interference technology, we show that cells deficient in KLF5 have increased sensitivity to DNA damage, regardless of p53 status. Both p53 and p53-dependent factors are unaffected by KLF5 depletion. Instead, the apoptotic phenotype consequent to damage is associated with reduced bad phosphorylation, and downregulation of Pim1. Consistently, transfection of wild-type Pim1 is sufficient to rescue this phenotype. Previous data have shown a number of putative Sp1-binding consensus sequences on the Pim1 promoter. Remarkably, chromatin immunoprecipitation studies show that KLF5 binds to the Pim1 promoter, and that binding increases soon after damage. These results identify a novel, p53-independent apoptotic pathway through which KLF5 functions in response to DNA damage. Therapeutic deregulation of this pathway could be used to modulate chemosensitivity.

Using array-comparative genomic hybridization to define molecular portraits of primary breast cancers

We analysed 148 primary breast cancers using BAC-arrays containing 287 clones representing cancer-related gene/loci to obtain genomic molecular portraits. Gains were detected in 136 tumors (91.9%) and losses in 123 tumors (83.1%). Eight tumors (5.4%) did not have any genomic aberrations in the 281 clones analysed. Common (more than 15% of the samples) gains were observed at 8q11-qtel, 1q21-qtel, 17q11-q12 and 11q13, whereas common losses were observed at 16q12-qtel, 11ptel-p15.5, 1p36-ptel, 17p11.2-p12 and 8ptel-p22. Patients with tumors registering either less than 5% (median value) or less than 11% (third quartile) total copy number changes had a better overall survival (log-rank test: P=0.0417 and P=0.0375, respectively). Unsupervised hierarchical clustering based on copy number changes identified four clusters. Women with tumors from the cluster with amplification of three regions containing known breast oncogenes (11q13, 17q12 and 20q13) had a worse prognosis. The good prognosis group (Nottingham Prognostic Index (NPI) <or=3.4) tumors had frequent loss of 16q24-qtel. Genes significantly associated with estrogen receptor (ER), Grade and NPI were used to build k-nearest neighbor (KNN) classifiers that predicted ER, Grade and NPI status in the test set with an average misclassification rate of 24.7, 25.7 and 35.7%, respectively. These data raise the prospect of generating a molecular taxonomy of breast cancer based on copy number profiling using tumor DNA, which may be more generally applicable than expression microarray analysis.

p300 is required for orderly G1/S transition in human cancer cells

The role of the transcriptional coactivator p300 in cell cycle control has not been analysed in detail due to the lack of appropriate experimental systems. We have now examined cell cycle progression of p300-deficient cancer cell lines, where p300 was disrupted either by gene targeting (p300(-) cells) or knocked down using RNAi. Despite significant proliferation defects under normal growth conditions, p300-deficient cells progressed rapidly through G1 with premature S-phase entry. Accelerated G1/S transition was associated with early retinoblastoma (RB) hyperphosphorylation and activation of E2F targets. The p300-acetylase activity was dispensable since expression of a HAT-deficient p300 mutant reversed these changes. Co-immunoprecipitation showed p300/RB interaction occurs in vivo during G1, and this interaction has two peaks: in early G1 with unphosphorylated RB and in late G1 with phosphorylated RB. In vitro kinase assays showed that p300 directly inhibits cdk6-mediated RB phosphorylation, suggesting p300 acts in early G1 to prevent RB hyperphosphorylation and delay premature S-phase entry. Paradoxically, continued cycling of p300(-) cells despite prolonged serum depletion was observed, and this occurred in association with persistent RB hyperphosphorylation. Altogether, these results suggest that p300 has an important role in G1/S control, possibly by modulating RB phosphorylation.

Absence of p300 induces cellular phenotypic changes characteristic of epithelial to mesenchyme transition

p300 is a transcriptional cofactor and prototype histone acetyltransferase involved in regulating multiple cellular processes. We generated p300 deficient (p300⁻) cells from the colon carcinoma cell line HCT116 by gene targeting. Comparison of epithelial and mesenchymal proteins in p300⁻ with parental HCT116 cells showed that a number of genes involved in cell and extracellular matrix interactions, typical of ‘epithelial to mesenchyme transition’ were differentially regulated at both the RNA and protein level. p300⁻ cells were found to have aggressive ‘cancer’ phenotypes, with loss of cell–cell adhesion, defects in cell–matrix adhesion and increased migration through collagen and matrigel. Although migration was shown to be metalloproteinase mediated, these cells actually showed a downregulation or no change in the level of key metalloproteinases, indicating that changes in cellular adhesion properties can be critical for cellular mobility.

A simple and reliable pretreatment protocol facilitates fluorescent in situ hybridisation on tissue microarrays of paraffin wax embedded tumour samples

AIMS

To describe a robust pretreatment protocol for preparing paraffin wax embedded tissues on tissue microarrays for fluorescence in situ hybridisation (FISH). The newly developed pretreatment protocol described here was compared with the commonly used sodium thiocyanate based protocol and two different heating methods used in standard antigen unmasking protocols for immunohistochemistry (pressure cooking and microwaving in citrate acid buffer).

METHODS

Dewaxed tissue sections were incubated in 10mM citric acid buffer at 80 degrees C for 30 minutes to two hours, followed by a short pepsin digestion (1-5 mg/ml). Pretreated tissues were co-denatured with DNA probes at 80 degrees C for 10 minutes, followed by hybridisation at 37 degrees C for 48-72 hours.

RESULTS

The three protocols using citrate acid buffer produced FISH signals with superior signal to noise ratios compared with sodium thiocyanate pretreatment. Most importantly, the best tissue attachment was achieved using the newly developed pretreatment protocol: on tissue microarrays less than 1% of cores were lost. To date, a total of 30 probes have been successfully hybridised on to breast tissue and multi-tissue microarrays.

CONCLUSION

This pretreatment protocol is easy, reproducible, and facilitates FISH on tissue microarrays, with potential for widespread application in cancer research.

Mutation analysis of CBP and PCAF reveals rare inactivating mutations in cancer cell lines but not in primary tumours

In this study we screened the histone acetyltransferases CBP and PCAF for mutations in human epithelial cancer cell lines and primary tumours. We identified two CBP truncations (both in cell lines), seven PCAF missense variants and four CBP intronic microdeletions. These data suggest that neither gene is commonly inactivated in human epithelial cancers.

Ventilator-associated pneumonia

Mechanically ventilated patients are at a substantially higher risk for developing nosocomial pneumonia. Overall, there is a relatively constant 1&!TN!150;3% risk per day of developing pneumonia while receiving mechanical ventilation. The sensitivity and specificity of clinical criteria alone for diagnosis of ventilator-associated pneumonias (VAP) is low. Several techniques have been developed to sample and quantitate the lower respiratory tract to improve the diagnostic yield. Gram-negative bacillary pneumonias account for the majority of the VAP. Strategies for prevention of VAP such as use of sucralfate for stress ulcer prophylaxis and selective decontamination of the digestive tract have been the focus of many clinical studies. Cost-effective preventive measures are needed to combat the increasing antimicrobial resistance, growing population of immunocompromised patients and increasing number of mechanically ventilated patients.