Bhuvanesh Singh

Primary mucosal malignant melanoma of the head and neck

The relative rarity of mucosal melanomas of the head and neck (MMHN) has made analysis of treatment approaches difficult. Advances in diagnostic techniques and treatment interventions have had obvious impact on outcomes in cutaneous melanoma, but the effects on outcome in MMHN remain undefined. This study aims to assess the outcome and identify clinical and histologic prognostic indicators in a recent cohort of patients with MMHN treated at a single institution.

Follicular Variant of Papillary Thyroid Carcinoma A Clinicopathologic Study of a Problematic Entity

There is continuous debate regarding the optimal classification, prognosis, and treatment of the follicular variant of papillary thyroid carcinoma (FVPTC). The objective of this study was to assess the behavior of FVPTC, especially its encapsulated form, and shed more light on its true position in the classification scheme of well differentiated thyroid carcinoma.

Factors associated with complications in microvascular reconstruction of head and neck defects.

The use of microvascular free tissue transfer has allowed the reconstruction of increasingly complex defects in higher risk patients after head and neck cancer resections. However, the combination of these factors also gives rise to a higher risk for the development of complications. This study was performed to establish the pretreatment factors associated with complication development after microvascular free tissue transfer for the reconstruction of defects resulting from head and neck cancer ablations, with particular attention to the role of comorbid conditions. A retrospective cohort study was conducted including 200 consecutive microvascular free tissue transfers performed for the reconstruction of surgical defects in the head and neck region at a single tertiary care institution. Comorbidity severity was assessed using the Charlson comorbidity index, a novel approach to comorbid staging in this setting. The flap survival rate was 98 percent. Complications developed in 56 cases (28 percent), with multiple complications occurring in 21 of these cases (10.5 percent). Univariate analysis revealed that prior radiation treatment (p = 0.03), anesthesia time over 10 hours (0.05), and advanced Charlson comorbidity grade (0.002) were associated with an increased risk for the development of complications. However, only the presence of advanced Charlson grade proved significant after multivariate analysis (odds ratio 3.9; 95 percent CI = 1.5 to 10.1). In addition, increasing Charlson grade (p = 0.003) and age over 70 years (p = 0.04) correlated with increasing complication severity. Systemic complications occurred in 28 patients (14 percent), with advanced Charlson grade being the only significant factor associated with the development of complications after controlling for confounding factors (odds ratio 3.8; 95 percent CI = 1.5 to 9.7). In patients over 70 years of age, increasing operative time also impacted on the development of systemic complications (p = 0.002), especially in patients with advanced Charlson grades (0.01). Recipient site complications occurred in 30 patients (15 percent), with history of prior radiation therapy being the only factor associated with increased risk by multivariate analysis (odds ratio 2.5; 95 percent CI = 1.1 to 5.7). No factors predicted the development of donor-site complications, which occurred in 11 cases (5.5 percent). The median hospital stay for the entire population was 16 days. The development of complications increased the median hospital stay by 7.5 days (p < 0.001). The effect of the development of complication on hospital stay remained significant even after controlling for the effects of confounding variables (relative risk = 9.87; 95 percent CI = 5.9 to 19.9). Microvascular surgery is a highly successful and relatively safe method for the reconstruction of large head and neck defects. The Charlson comorbidity index grading may be useful for identifying patients at increased risk for the development of complications after microvascular reconstruction, allowing for improved perioperative planning. In addition, patients with prior radiation exposure have a significantly higher risk for developing complications at the recipient site. Although advanced age is not associated with an increased risk for complications, older patients may be more sensitive to the effects of prolonged anesthesia and are likely to develop more severe complications.

A CK2-Dependent Mechanism for Degradation of the PML Tumor Suppressor

The PML tumor suppressor controls key pathways for growth suppression, induction of apoptosis, and cellular senescence. PML loss occurs frequently in human tumors through unknown posttranslational mechanisms. Casein kinase 2 (CK2) is oncogenic and frequently upregulated in human tumors. Here we show that CK2 regulates PML protein levels by promoting its ubiquitin-mediated degradation dependent on direct phosphorylation at Ser517. Consequently, PML mutants that are resistant to CK2 phosphorylation display increased tumor-suppressive functions. In a faithful mouse model of lung cancer, we demonstrate that Pml inactivation leads to increased tumorigenesis. Furthermore, CK2 pharmacological inhibition enhances the PML tumor-suppressive property in vivo. Importantly, we found an inverse correlation between CK2 kinase activity and PML protein levels in human lung cancer-derived cell lines and primary specimens. These data identify a key posttranslational mechanism that controls PML protein levels and provide therapeutic means toward PML restoration through CK2 inhibition.

COMPLICATIONS OF CRANIOFACIAL RESECTION FOR MALIGNANT TUMORS OF THE SKULL BASE: REPORT OF AN INTERNATIONAL COLLABORATIVE STUDY

Advances in imaging, surgical technique, and perioperative care have made craniofacial resection (CFR) an effective and safe option for treating malignant tumors involving the skull base. The procedure does, however, have complications. Because of the relative rarity of these tumors, most existing data on postoperative complications come from individual reports of relatively small series of patients. This international collaborative report examines a large cohort of patients accumulated from multiple institutions with the aim of identifying patient‐related and tumor‐related predictors of postoperative morbidity and mortality and set a benchmark for future studies.

Prospective functional voice assessment in patients undergoing thyroid surgery.

ObjectiveTo analyze voice function before and after thyroidectomy for patients with normal preoperative voice using a standardized multidimensional voice assessment protocol. Summary Background DataThe natural history of post-thyroidectomy voice disturbances for patients with preserved laryngeal nerve function has not been systematically studied and characterized with the intent of using the data for postoperative voice rehabilitation. MethodsDuring a prospective single-arm study, patients with normal voice underwent functional voice testing using a standardized voice grading scale and a battery of acoustic, aerodynamic, glottographic, and videostroboscopic tests before, 1 week after, and 3 months after thyroidectomy. Differences in observed sample means were evaluated using analysis of covariance or t test; categorical data was analyzed using the Fisher exact or chi-square test. ResultsFifty-four patients were enrolled; 50 and 46 were evaluable at 1 week and 3 months, respectively. No patient developed recurrent laryngeal nerve injury; one had superior laryngeal nerve injury. Fifteen (30%) patients reported early subjective voice change and seven (14%) reported late (3-month) subjective voice change. Forty-two (84%) patients had significant objective change in at least one voice parameter. Six (12%) had significant alterations in more than three voice measures, of which four (67%) were symptomatic, whereas 25% with three or fewer objective changes had symptoms. Patients with persistent voice change at 3 months had an increased likelihood of multiple (more than three) early objective changes (43% vs. 7%). Early maximum phonational frequency range and vocal jitter changes from baseline were significantly associated with voice symptoms at 3 months. ConclusionsEarly vocal symptoms are common following thyroidectomy and persist in 14% of patients. Multiple (more than three) objective voice changes correlate with early and late postoperative symptoms. Alterations in maximum phonational frequency range and vocal jitter predict late perceived vocal changes. Factors other than laryngeal nerve injury appear to alter post-thyroidectomy voice. The variability of patient symptoms underscores the importance of understanding the physiology of dysphonia.

The mutational landscape of adenoid cystic carcinoma

Adenoid cystic carcinomas (ACCs) are among the most enigmatic of human malignancies. These aggressive salivary gland cancers frequently recur and metastasize despite definitive treatment, with no known effective chemotherapy regimen. Here we determined the ACC mutational landscape and report the exome or whole-genome sequences of 60 ACC tumor-normal pairs. These analyses identified a low exonic somatic mutation rate (0.31 non-silent events per megabase) and wide mutational diversity. Notably, we found mutations in genes encoding chromatin-state regulators, such as SMARCA2, CREBBP and KDM6A, suggesting that there is aberrant epigenetic regulation in ACC oncogenesis. Mutations in genes central to the DNA damage response and protein kinase A signaling also implicate these processes. We observed MYB-NFIB translocations and somatic mutations in MYB-associated genes, solidifying the role of these aberrations as critical events in ACC. Lastly, we identified recurrent mutations in the FGF-IGF-PI3K pathway (30% of tumors) that might represent new avenues for therapy. Collectively, our observations establish a molecular foundation for understanding and exploring new treatments for ACC.

Validation of the Charlson Comorbidity Index in Patients With Head and Neck Cancer: A Multi‐institutional Study

Comorbid conditions are medical illnesses that accompany cancer. The impact of these conditions on the outcome of patients with head and neck cancer is well established. However, all of the comorbidity studies in patients with head and neck cancer reported in the literature have been performed using the Kaplan‐Feinstein index (KFI), which may be too complicated for routine use. This study was performed to introduce and validate the use of the Charlson comorbidity index (CI) in patients with head and neck cancer and to compare it with the Kaplan‐Feinstein comorbidity index for accuracy and ease of use. Study design was a retrospective cohort study. The study population was drawn for three academic tertiary care centers and included 88 patients 45 years of age and under who underwent curative treatment for head and neck cancer. All patients were staged by the KFI and the CI for comorbidity and divided into two groups based on the comorbidity severity staging. Group 1 included patients with advanced comorbidity (stages 2 or 3), and group 2 included those with low‐level comorbidity (stages 0 or 1). Outcomes were compared based on these divisions. The KFI was successfully applied to 80% of this study population, and the CI was successfully applied in all cases ( P < 0.0001). In addition, the KFI was found to be more difficult to use than the CI ( P < 0.0001). However, both indices independently predicted the tumor‐specific survival ( P = 0.007), even after adjusting for the confounding effects of TNM stage by multivariate analysis. Overall, the CI was found to be a valid prognostic indicator in patients with head and neck cancer. In addition, because comorbidity staging by the CI independently predicted survival, was easier to use, and more readily applied, it may be better suited for use for retrospective comorbidity studies.

Craniofacial resection for malignant paranasal sinus tumors: Report of an international collaborative study

Malignant tumors of the superior sinonasal vault are rare, and, because of this and the varied histologic findings, most outcomes data reflect the experience of small patient cohorts. This International Collaborative study examines a large cohort of patients accumulated from multiple institutions experienced in craniofacial surgery, with the aim of reporting benchmark figures for outcomes and identifying patient‐related and tumor‐related predictors of prognosis after craniofacial resection (CFR).

The tyrosine phosphatase PTPRD is a tumor suppressor that is frequently inactivated and mutated in glioblastoma and other human cancers

Tyrosine phosphorylation plays a critical role in regulating cellular function and is a central feature in signaling cascades involved in oncogenesis. The regulation of tyrosine phosphorylation is coordinately controlled by kinases and phosphatases (PTPs). Whereas activation of tyrosine kinases has been shown to play vital roles in tumor development, the role of PTPs is much less well defined. Here, we show that the receptor protein tyrosine phosphatase delta (PTPRD) is frequently inactivated in glioblastoma multiforme (GBM), a deadly primary neoplasm of the brain. PTPRD is a target of deletion in GBM, often via focal intragenic loss. In GBM tumors that do not possess deletions in PTPRD, the gene is frequently subject to cancer-specific epigenetic silencing via promoter CpG island hypermethylation (37%). Sequencing of the PTPRD gene in GBM and other primary human tumors revealed that the gene is mutated in 6% of GBMs, 13% of head and neck squamous cell carcinomas, and in 9% of lung cancers. These mutations were deleterious. In total, PTPRD inactivation occurs in >50% of GBM tumors, and loss of expression predicts for poor prognosis in glioma patients. Wild-type PTPRD inhibits the growth of GBM and other tumor cells, an effect not observed with PTPRD alleles harboring cancer-specific mutations. Human astrocytes lacking PTPRD exhibited increased growth. PTPRD was found to dephosphorylate the oncoprotein STAT3. These results implicate PTPRD as a tumor suppressor on chromosome 9p that is involved in the development of GBMs and multiple human cancers.