Mitochondrial Mutations in Adenoid Cystic Carcinoma of the Salivary Glands

Background: The MitoChip v2.0 resequencing array is an array-based technique allowing for accurate and complete sequencing of the mitochondrial genome. No studies have investigated mitochondrial mutation in salivary gland adenoid cystic carcinomas. Methodology: The entire mitochondrial genome of 22 salivary gland adenoid cystic carcinomas (ACC) of salivary glands and matched leukocyte DNA was sequenced to determine the frequency and distribution of mitochondrial mutations in ACC tumors. Principal Findings: Seventeen of 22 ACCs (77%) carried mitochondrial mutations, ranging in number from 1 to 37 mutations. A disproportionate number of mutations occurred in the D-loop. Twelve of 17 tumors (70.6%) carried mutations resulting in amino acid changes of translated proteins. Nine of 17 tumors (52.9%) with a mutation carried an amino acid changing mutation in the nicotinamide adenine dinucleotide dehydrogenase (NADH) complex. Conclusions/Significance: Mitochondrial mutation is frequent in salivary ACCs. The high incidence of amino acid changing mutations implicates alterations in aerobic respiration in ACC carcinogenesis. D-loop mutations are of unclear significance

Coordinated Activation of Candidate Proto-Oncogenes and Cancer Testes Antigens via Promoter Demethylation in Head and Neck Cancer and Lung Cancer

Background: Epigenetic alterations have been implicated in the pathogenesis of solid tumors, however, proto-oncogenes activated by promoter demethylation have been sporadically reported. We used an integrative method to analyze expression in primary head and neck squamous cell carcinoma (HNSCC) and pharmacologically demethylated cell lines to identify aberrantly demethylated and expressed candidate proto-oncogenes and cancer testes antigens in HNSCC. Methodology/Principal Findings: We noted coordinated promoter demethylation and simultaneous transcriptional upregulation of proto-oncogene candidates with promoter homology, and phylogenetic footprinting of these promoters demonstrated potential recognition sites for the transcription factor BORIS. Aberrant BORIS expression correlated with upregulation of candidate proto-oncogenes in multiple human malignancies including primary non-small cell lung cancers and HNSCC, induced coordinated proto-oncogene specific promoter demethylation and expression in non-tumorigenic cells, and transformed NIH3T3 cells. Conclusions/Significance: Coordinated, epigenetic unmasking of multiple genes with growth promoting activity occurs i

Inactivation of the Tumor Suppressor Genes Causing the Hereditary Syndromes Predisposing to Head and Neck Cancer via Promoter Hypermethylation in Sporadic Head and Neck Cancers

Fanconi anemia (FA) and dyskeratosis congenita (DC) are rare inherited syndromes that cause head and neck squamous cell cancer (HNSCC). Prior studies of inherited forms of cancer have been extremely important in elucidating tumor suppressor genes inactivated in sporadic tumors. Here, we studied whether sporadic tumors have epigenetic silencing of the genes causing the inherited forms of HNSCC. Using bisulfite sequencing, we investigated the incidence of promoter hypermethylation of the 17 Fanconi- and DC-associated genes in sporadic HNSCC. Genes that only showed methylation in the tumor patients were chosen for quantitative methylation-specific PCR (qMSP) in a set of 45 tumor and 16 normal patients. Three gene promoters showed differences in methylation: FancB (FAAP95, FA core complex), FancJ (BRIP1, DNA Helicase/ATPase), and DKC1 (dyskeratin). Bisulfite sequencing revealed that only FancB and DKC1 showed no methylation in normal patients, yet the presence of promoter hypermethylation in tumor patients. On qMSP, 1/16 (6.25%) of the normal mucosal samples from non-cancer patients and 14/45 (31.1%) of the tumor patients demonstrated hypermethylation of the FancB locus (p < 0.05). These results suggest that inactivation of FancB may play a role in the pathogenesis of sporadic HNSCC

Single-Stage Bipedicle Local Tissue Transfer and Skin Graft for Achilles Tendon and Posterior Heel Wound Complications

Category: Ankle Introduction/Purpose: Achilles tendon and posterior heel wound complications are difficult to treat. These typically require soft tissue coverage via microvascular free tissue transfer at a tertiary referral center. Here we describe coverage of a series of posterior heel and achilles wounds via simple, local tissue transfer, a bipedicle fasciocutaneous flap. This surgical technique can be performed by an orthopaedic foot and ankle surgeon without resources of tertiary/specialized care or microvascular support. Methods: Three patients with separate pathologies were treated with a single-stage bipedicle fasciocutaneous local tissue transfer. Case 1 was a patient with wound breakdown following midsubstance Achilles tendon repair. Case 2 was a patient with insertional wound breakdown after Achilles debridement and repair to the calcaneus. Case 3 was a heel venous stasis ulcer with calcaneal exposure in a diabetic vasculopath. All three cases were treated with the following technique: an incision was immediately posterior to the lateral malleolus. The length of the incision was approximately 25% greater than the proximal to distal measurement of the wound. The dissection was carried to the flexor retinaculum and carried posteriorly to create a fasciocutaneous flap attached proximally and distally. This flap was then mobilized posteriorly to close the desired defect, leaving an ellipsoid shaped skin defect laterally. A split thickness skin graft was used to cover the defect created by the flap transposition. Results: All three patients demonstrated initial complete healing of the posterior defect, lateral ankle skin graft recipient site, and the skin graft donor site following surgery. Case 3 had a subsequent recurrent ulceration after initial healing. This was superficial and healed with local wound care. All patients regained full preoperative range of motion and were able to ambulate independently without modified footwear. Conclusion: The bipedicled fasciocutaneous flap described offers a simple, predictable single stage procedure that can be accomplished by an orthopaedic foot and ankle surgeon without resources of a tertiary care center for posterior foot and ankle defects. This flap allows for relatively short operative times and can be customized to facilitate defect coverage. Ultimately, the flap is sufficiently durable to withstand the local tissue stresses required for ambulation at an early stage. This provides a reasonable alternative to complicated and time consuming microvascular reconstruction, but does require careful follow-up to manage the patient’s underlying comorbid conditions that may complicate wound healing

Frequency and phenotypic implications of mitochondrial DNA mutations in human squamous cell cancers of the head and neck

Mitochondrial genomic mutations are found in a variety of human cancers; however, the frequency of mitochondrial DNA (mtDNA) mutations in coding regions remains poorly defined, and the functional effects of mitochondrial mutations found in primary human cancers are not well described. Using MitoChip, we sequenced the whole mitochondrial genome in 83 head and neck squamous cell carcinomas. Forty-one of 83 (49%) tumors contained mtDNA mutations. Mutations occurred within noncoding (D-loop) and coding regions. A nonrandom distribution of mutations was found throughout the mitochondrial enzyme complex components. Sequencing of margins with dysplasia demonstrated an identical nonconservative mitochondrial mutation (A76T in ND4L) as the tumor, suggesting a role of mtDNA mutation in tumor progression. Analysis of p53 status showed that mtDNA mutations correlated positively with p53 mutations (P < 0.002). To characterize biological function of the mtDNA mutations, we cloned NADH dehydrogenase subunit 2 (ND2) mutants based on primary tumor mutations. Expression of the nuclear-transcribed, mitochondrial-targeted ND2 mutants resulted in increased anchorage-dependent and -independent growth, which was accompanied by increased reactive oxygen species production and an aerobic glycolytic metabolic phenotype with hypoxia-inducible factor (HIF)-1α induction that is reversible by ascorbate. Cancer-specific mitochondrial mutations may contribute to development of a malignant phenotype by direct genotoxic effects from increased reactive oxygen species production as well as induction of aerobic glycolysis and growth promotion