Nuclear localization of glutamate-cysteine ligase is associated with proliferation in head and neck squamous cell carcinoma.

Glutathione (GSH) is the keystone of the cellular response toward oxidative stress. Elevated GSH content correlates with increased resistance to chemotherapy and radiotherapy of head and neck (HN) tumors. The purpose of the present cross-sectional study was to evaluate whether the expression of glutamate-cysteine ligase (GCL) accounts for the increased GSH availability observed in HN squamous cell carcinoma (SCC). For that purpose, the messenger (m)RNA levels of the modifier (M) and catalytic (C) subunits of GCL and its putative regulators (namely, nuclear factor erythroid 2-related factor 2, heme oxygenase-1 and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha) were monitored in 35 surgical resections of untreated HNSCC. The localization of GCLM was evaluated using in situ hybridization and immunohistochemistry. GCLM expression was significantly increased in tumor samples, compared with normal mucosa, both at the mRNA and protein level (P=0.029), but the pathway of GCLM activation remains to be elucidated. Protein expression of GCLM was detected in the cytoplasm and nucleus. GCLM and the proliferation marker Ki-67 displayed a similar distribution, being both mainly expressed at the periphery of tumor lobules. The present study reported increased expression of GCL and the rate-limiting enzyme of GSH synthesis, within HNSCC. The nuclear localization of GCLM and the concomitant expression of Ki-67 suggested that the localization of GSH synthesis contributes to the protection against oxidative stress within hotspots of cell proliferation.

Thyroid surgery with a harmonic scalpel: an experimental study.

BACKGROUND: The goal of the study was to determinate the safety of the harmonic scalpel, widely used in thyroidectomy, near the recurrent laryngeal nerve (RLN). METHODS: The study involved ten pigs of either sex. Twenty RLNs at risk were dissected using the new harmonic scalpel FOCUS. The distances between the nerve and the activated instrument were checked with a millimeter ruler. After dissection, the pigs were euthanized, and both RLNs were fixed in formol and examined by histology after staining with hematoxylin-eosin. Due to technical reasons, only 18 RLNs from the ten pigs could be examined. RESULTS: In the experiment that investigated the extent of heat injury, ultrasonic dissection did not cause any immediate damage of the nerve even close to the RLN (1 mm away from the RLN). CONCLUSION: The use of harmonic scalpel FOCUS for thyroid surgery is safe for the surrounding structures (nerves). Careful tissue applications of the device near the RLN (1 mm) did not cause any lesion histologically.

Sentinel Node in Oral Cancer: The Nuclear Medicine Aspects. A Survey from the Sentinel European Node Trial.

PURPOSE: Nuclear imaging plays a crucial role in lymphatic mapping of oral cancer. This evaluation represents a subanalysis of the original multicenter SENT trial data set, involving 434 patients with T1-T2, N0, and M0 oral squamous cell carcinoma. The impact of acquisition techniques, tracer injection timing relative to surgery, and causes of false-negative rate were assessed. METHODS: Three to 24 hours before surgery, all patients received a dose of Tc-nanocolloid (10-175 MBq), followed by lymphoscintigraphy. According to institutional protocols, all patients underwent preoperative dynamic/static scan and/or SPECT/CT. RESULTS: Lymphoscintigraphy identified 723 lymphatic basins. 1398 sentinel lymph nodes (SNs) were biopsied (3.2 SN per patient; range, 1-10). Dynamic scan allowed the differentiation of sentinel nodes from second tier lymph nodes. SPECT/CT allowed more accurate anatomical localization and estimated SN depth more efficiently. After pathological examination, 9.9% of the SN excised (138 of 1398 SNs) showed metastases. The first neck level (NL) containing SN+ was NL I in 28.6%, NL IIa in 44.8%, NL IIb in 2.8%, NL III in 17.1%, and NL IV in 6.7% of positive patients. Approximately 96% of positive SNs were localized in the first and second lymphatic basin visualized using lymphoscintigraphy. After neck dissection, the SN+ was the only lymph node containing metastasis in approximately 80% of patients. CONCLUSIONS: Best results were observed using a dynamic scan in combination with SPECT/CT. A shorter interval between tracer injection, imaging, and surgery resulted in a lower false-negative rate. At least 2 NLs have to be harvested, as this may increase the detection of lymphatic metastases.

Prognostic value of lymph node ratio for locoregional failure in patients with advanced head and neck cancers.

BACKGROUND: In the current study, the utility of lymph node ratio (LNR) was evaluated as an alternative method for predicting locoregional failure in patients with advanced head and neck cancer. METHODS: Fifty-six patients with oral and (pharyngo)laryngeal squamous cell carcinoma were included. Among those, 48 were males and 8 females, with a mean age of 58 years. The primary tumor was located in the oral cavity in 16 cases, involved the larynx in 17 cases and the hypopharynx in 23 cases. All the tumors were staged T4. We carried out 112 neck dissections. All the lymph nodes harvested from the neck dissection were carefully examined, with LNR calculated as the ratio of positive lymph nodes to total lymph nodes removed. All the patients received adjuvant (chemo)radiotherapy. RESULTS: Receiver operating characteristic curve analysis showed LNR was significantly associated with locoregional failure. LNR >0.09 (as the cutoff point) could predict locoregional failure after surgery for oral and (pharyngo)laryngeal cancers with a sensibility of 93% and specificity of 100%. CONCLUSIONS: After surgery, pathologic evaluation of the neck using LNR was found to reliably predict the risk of locoregional recurrence in patients with advanced head and neck cancers.

Sentinel European Node Trial (SENT): 3-year results of sentinel node biopsy in oral cancer.

PURPOSE: Optimum management of the N0 neck is unresolved in oral cancer. Sentinel node biopsy (SNB) can reliably detect microscopic lymph node metastasis. The object of this study was to establish whether the technique was both reliable in staging the N0 neck and a safe oncological procedure in patients with early-stage oral squamous cell carcinoma. METHODS: An European Organisation for Research and Treatment of Cancer-approved prospective, observational study commenced in 2005. Fourteen European centres recruited 415 patients with radiologically staged T1-T2N0 squamous cell carcinoma. SNB was undertaken with an average of 3.2 nodes removed per patient. Patients were excluded if the sentinel node (SN) could not be identified. A positive SN led to a neck dissection within 3 weeks. Analysis was performed at 3-year follow-up. RESULTS: An SN was found in 99.5% of cases. Positive SNs were found in 23% (94 in 415). A false-negative result occurred in 14% (15 in 109) of patients, of whom eight were subsequently rescued by salvage therapy. Recurrence after a positive SNB and subsequent neck dissection occurred in 22 patients, of which 16 (73%) were in the neck and just six patients were rescued. Only minor complications (3%) were reported following SNB. Disease-specific survival was 94%. The sensitivity of SNB was 86% and the negative predictive value 95%. CONCLUSION: These data show that SNB is a reliable and safe oncological technique for staging the clinically N0 neck in patients with T1 and T2 oral cancer. EORTC Protocol 24021: Sentinel Node Biopsy in the Management of Oral and Oropharyngeal Squamous Cell Carcinoma.

Long term results of sentinel lymph node biopsy in early oral squamous cell carcinoma.

The objective of the study was to evaluate the long term results of the sentinel node (SN) biopsy technique in the management of the clinically negative (N0) neck in patients with early oral squamous cell carcinoma (T1-T2). Patients with positive SN underwent neck dissection. A sentinel lymph node (SLN) biopsy was performed on 31 consecutive patients. Six of the 31 patients were upstaged by the results of the SLN biopsy. The SLN biopsy allowed the identification of node metastasis in 100% of the cases with a sensitivity of 100%, specificity of 100%, and negative predictive value of 100%. There was a mean follow-up of 59 months. The neck control rate was 100% in the SLN negative group and two SLN positive patients developed subsequent neck disease (neck control rate of 88%). One SLN patient presented at the follow-up with a second primary tumor, 18 months later treated successfully by chemoradiotherapy. The overall survival rate was 100% in both groups. The promising reported short-term results have been sustained by long term follow-up. Patients with negative SLN achieved an excellent neck control rate. The neck control rate in SN negative patients was superior to that in SLN positive patients, but not statistically different.

Assessment of oxidative stress in tumors and histologically normal mucosa from patients with head and neck squamous cell carcinoma: a preliminary study.

Over 90% of head and neck cancers are squamous cell carcinomas (HNSCC) and the overall 5-year survival rate is up to 50%. The redox status of these cancers is an important factor in carcinogenesis and plays a role in radioresistance and therefore locoregional recurrences. However, knowledge of the redox status is rather limited. Glutathione is the major reactive oxygen species scavenger in normal cells. We compared the levels of tissue redox potential in HNSCC tumor tissue and compared them with those of the adjacent, histologically cancer-free, mucosa. A total of 36 patients with HNSCC were included in the study. The redox status of tumor and normal adjacent tissue was measured by the oxidized/reduced glutathione (GSSG/GSH) ratio in capillary electrophoresis. The GSSG/GSH ratio in the tumor tissue was lower compared with adjacent normal tissue in 38% of the patients. Pretherapy HNSCC tumor tissue has variable GSH levels compared with adjacent cancer-free mucosa. This difference was not related to clinical and pathological parameters. Further studies are required to determine whether the GSSG/GSH ratio plays a role in carcinogenesis and could predict radioresistance.

The role of EGFR-targeting strategies in the treatment of head and neck cancer.

With its targeted mechanism of action and synergistic activity with current treatment modalities, cetuximab is a potentially valuable treatment option for patients with recurrent and/or metastatic squamous cell cancer of the head and neck who have progressed on cisplatin-based chemotherapy. The use of cetuximab in combination with radiotherapy as definitive treatment for locoregionally advanced squamous cell cancer of the head and neck is generally restricted to patients unfit to receive cisplatin-based chemoradiation, which is still considered the standard of care. The effect of this epidermal growth factor receptor antagonist occurs without any change in the pattern and the severity of toxicity usually associated with head and neck radiation.

Association of duoxes with thyroid peroxidase and its regulation in thyrocytes.

CONTEXT: Thyroid hormone synthesis requires H(2)O(2) produced by dual oxidases (Duoxes) and thyroperoxidase (TPO). Defects in this system lead to congenital hypothyroidism. H(2)O(2) damage to the thyrocytes may be a cause of cancer. OBJECTIVE: The objective of the study was to investigate whether Duox and TPO, the H(2)O(2) producer and consumer, might constitute a complex in the plasma membrane of human thyroid cells, thus maximizing efficiency and minimizing leakage and damage. DESIGN: The interaction between Duox and TPO was studied by coimmunoprecipitation and Western blotting of plasma membranes from incubated follicles prepared from freshly resected human thyroid tissue from patients undergoing thyroidectomy, and COS-7 cells transiently transfected with the entire Duoxes or truncated [amino (NH2) or carboxyl (COOH) terminal]. RESULTS: The following results were reached: 1) Duox and TPO from membranes are coprecipitated, 2) this association is up-regulated through the Gq-phospholipase C-Ca(2+)-protein kinase C pathway and down-regulated through the Gs-cAMP-protein kinase A pathway, 3) H(2)O(2) increases the association of Duox1 and Duox2 to TPO in cells and in membranes, and 4) truncated NH(2)- or COOH-terminal Duox1 and Duox2 proteins show different binding abilities with TPO. CONCLUSION: Coimmunoprecipitations show that Duox and TPO locate closely in the plasma membranes of human thyrocytes, and this association can be modulated by H(2)O(2), optimizing working efficiency and minimizing H(2)O(2) spillage. This association could represent one part of a postulated pluriprotein complex involved in iodination. This suggests that defects in this association could impair thyroid hormone synthesis and lead to thyroid insufficiency and cell damage.

Tumour characteristics and therapeutic results after percutaneous radiofrequency ablation of secondary lung neoplasms.

INTRODUCTION: The objective was to assess the efficacy of percutaneous radiofrequency ablation (RFA) in the treatment of secondary lung tumours and evaluation of the treatment's results by contrast-enhanced CT scan. MATERIAL AND METHODS: Fifteen secondary lung neoplasms in 10 patients (mean age 64.3 years) had pulmonary radiofrequency and imaging follow-up. All the patients had absolute contraindications to the surgery. The procedure was performed under computed tomography (CT) guidance with anaesthesiologic assistance. The results were evaluated by post-procedural contrast-enhanced CT scan and CT scans 1, 3, 6, 9 and 12 months after the treatment. RESULTS: The median follow-up period was 26 months. A complete ablation according to the absence of enhancement after the procedure was obtained in all cases; pleural effusion was seen in 2 patients. The main adverse event was a pneumothorax, which occurred in 4 cases. A chest tube was required in two cases. A recurrence at the site of the treatment for one lesion was observed during a 12-month follow- up period. Three patients experienced systemic disease progression. In one of these 3 patients, this progression was associated with recurrence at the site of the treatment. CONCLUSION: RFA seems to be possible for "non-surgical" patients with various histologic types of secondary lung tumours. Good results in terms of local tumour control validated by contrast-enhanced CT scan were observed during short-term follow-up evaluation.

Reciprocal negative regulation between thyrotropin/3',5'-cyclic adenosine monophosphate-mediated proliferation and caveolin-1 expression in human and murine thyrocytes.

The expression of caveolins is down-regulated in tissue samples of human thyroid autonomous adenomas and in the animal model of this disease. Because several cell types present in thyroid express caveolins, it remained unclear if this down-regulation occurs in thyrocytes and which are the mechanism and role of this down-regulation in the tumor context. Here we show that prolonged stimulation of isolated human thyrocytes by TSH/cAMP/cAMP-dependent protein kinase inhibits caveolins' expression. The expression of caveolins is not down-regulated by activators of other signaling pathways relevant to thyroid growth/function. Therefore, the down-regulation of caveolins' expression in autonomous adenomas is a direct consequence of the chronic activation of the TSH/cAMP pathway in thyrocytes. The down-regulation of caveolin-1 occurs at the mRNA level, with a consequent protein decrease. TSH/cAMP induces a transcription-dependent, translation-independent destabilization of the caveolin-1 mRNA. This effect is correlated to the known proliferative role of that cascade in thyrocytes. In vivo, thyrocytes of caveolin-1 knockout mice display enhanced proliferation. This demonstrates, for the first time, the in vivo significance of the specific caveolin-1 down-regulation by one mitogenic cascade and its relation to a human disease.

Does clinical and radiological response predict complete tumor control in N2-N3 squamous cell head and neck cancer after non-operative management of the neck?

CONCLUSION: A complete clinical and radiological response observed following chemotherapy and radiotherapy is not predictive of the absence of residual disease. Moreover, salvage neck surgery does not always seem to be an effective strategy. Consequently, early neck dissection should be advised for patients with complete clinical and radiological response (CCRR) after chemoradiotherapy for tumors with N2-N3 disease. BACKGROUND: We retrospectively reviewed the outcome of 28 patients with N2-N3 disease treated initially with chemotherapy and radiotherapy. PATIENTS AND METHODS: A neck dissection was performed for all patients with residual disease in the neck. RESULTS: A CCRR in the neck was achieved in 25 of 28 patients. The remaining three patients with residual neck mass underwent a salvage neck dissection: the pathological examination confirmed the persistence of tumoral disease. No regional failure was observed in these three patients. In 25 patients considered to have CCRR in the neck, 5 patients (20%) developed regional recurrence. Successful salvage approach was not possible for any of these patients.

Thyrotropin stimulates the generation of inositol 1,4,5-trisphosphate in human thyroid cells.

CONTEXT: Dual activation by TSH of the phospholipase C and cAMP cascades has been reported in human thyroid cells. In contrast, Singh et al. reported convincing data in FRTL-5 thyrocytes arguing against such an effect in this model. Their data in FRTL-5 cells indicated no increase in inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in response to TSH. Therefore, the authors questioned results previously obtained on human cells by cruder methodology. OBJECTIVE: We investigated the formation of inositol phosphates by HPLC techniques in human thyroid slices to separate the inositol phosphate isomers. RESULTS: Ins(1,4,5)P3, inositol 1,3,4-trisphosphate, and inositol 1,3,4,5-tetrakisphosphate were increased after TSH stimulation. The effect of TSH in human thyroid cells was reproduced by recombinant TSH and prevented by antibodies blocking the TSH receptor. Thyroid-stimulating antibodies at concentrations eliciting a cAMP response equivalent to TSH failed to stimulate inositol phosphate generation. CONCLUSIONS: TSH, but not thyroid-stimulating antibodies, activates both cAMP and the phospholipase C cascade in human thyroid as now demonstrated by an increase in Ins(1,4,5)P3 and its inositol phosphate metabolites. Therefore, this effect cannot be extrapolated to the FRTL-5 cell line. The apparent discrepancy may be due to a difference between species (human vs. rat) or to the loss of the fresh tissue properties in a cell line. The dual effect of TSH in human cells, through cAMP on secretion of thyroid hormones and through the diacylglycerol, Ins(1,4,5)P3 Ca2+ pathway on thyroid hormone synthesis, implies the possible separation of these effects in thyroid disease.