Quantitative proteome analysis of Merkel cell carcinoma cell lines using SILAC.

BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive neuroendocrine tumour of the skin with growing incidence. To better understand the biology of this malignant disease, immortalized cell lines are used in research for in vitro experiments. However, a comprehensive quantitative proteome analysis of these cell lines has not been performed so far. METHODS: Stable isotope labelling by amino acids in cell culture (SILAC) was applied to six MCC cell lines (BroLi, MKL-1, MKL-2, PeTa, WaGa, and MCC13). Following tryptic digest of labelled proteins, peptides were analysed by mass spectrometry. Proteome patterns of MCC cell lines were compared to the proteome profile of an immortalized keratinocyte cell line (HaCaT). RESULTS: In total, 142 proteins were upregulated and 43 proteins were downregulated. Altered proteins included mitoferrin-1, histone H2A type 1-H, protein-arginine deiminase type-6, heterogeneous nuclear ribonucleoproteins A2/B1, protein SLX4IP and clathrin light chain B. Furthermore, several proteins of the histone family and their variants were highly abundant in MCC cell lines. CONCLUSIONS: The results of this study present a new protein map of MCC and provide deeper insights in the biology of MCC. Data are available via ProteomeXchange with identifier PXD008181.

Ultrastructural morphology of a middle ear ceruminoma.

The ultrastructural morphology of a ceruminous gland adenoma in the middle ear was examined electron microscopically. The epithelial tumor cells displayed apocrine caps, microvilli, cell junctions, secretory granules, vacuoles, lipid droplets and siderosomes, which are the characteristic ultrastructural features of apocrine glands. Concentric membranous bodies of the endoplasmic reticulum, phagocytic activity of the tumor cells, intracytoplasmic lumina, ciliated cells and also spiny collagen in the tumor stroma could be seen. The myoepithelial cells are an important tumor marker in the differential diagnosis between ceruminomas and adenomas of the middle ear. The ectopic origin in the modified apocrine ceruminous glands, the specific localization, the clinical features and the extremely rare occurrence of the ceruminoma makes this tumor a unique neoplastic entity.

Advantages of recurrent laryngeal nerve identification in thyroidectomy and parathyroidectomy and the importance of preoperative and postoperative laryngoscopic examination in more than 1000 nerves at risk.

OBJECTIVES/HYPOTHESIS: Recurrent laryngeal nerve palsy (RLNP) is a major obstacle in thyroid and parathyroid surgery. Therefore, methods that reduce the number of temporary and, especially, permanent recurrent laryngeal nerve palsies are of great interest. One promising way to ensure the integrity of the recurrent laryngeal nerve (RLN) is to identify the nerve always. The first question raised in the present study was whether RLN preparation reduces the number of recurrent laryngeal nerve palsies or whether it introduces additional risks. Second, from former cases we know that the absence of postoperative hoarseness does not exclude RLNP, nor does postoperative hoarseness exclusively imply RLNP. Besides, misdiagnosis is not uncommon. Therefore, preoperative and postoperative laryngoscopic examination was given attention. STUDY DESIGN: Patients were investigated 1 to 7 days before and 3 to 7 days after surgery. When an RLNP was identified, patients were followed up in a 2-week rhythm the first few times and every 6 to 8 weeks thereafter until RLNP resolved or it was considered permanent after 2 years. METHODS: We prospectively investigated 608 surgical patients with 1080 nerves at risk. Because different diseases might have different rates of postoperative RLNP, we analyzed benign thyroid disease (680 nerves at risk), thyroid malignoma (321 nerves at risk), and hyperparathyroidism (79 nerves at risk) separately. Patients undergoing primary surgery (no prior thyroid surgery) and secondary interventions (there were one or more thyroid operations before this intervention) were evaluated separately. RESULTS: We found 3.4%, 7.2%, and 2.5% of temporary recurrent laryngeal nerve palsies per nerve in the benign thyroid disease, thyroid malignoma, and hyperparathyroidism groups, respectively. The prevalence of recurrent laryngeal nerve palsies in these groups was 0.3%, 1.2%, and 0%, respectively. Conforming with other studies, the total number of recurrent laryngeal nerve palsies (temporary and permanent) was not increased compared with cases with no RLN preparation, whereas the number of permanent recurrent laryngeal nerve palsies was markedly reduced. An RLN was always identifiable. Astonishingly, the restitution of an RLNP was up to 2 years in duration; however, most restitutions occurred within the first 6 months. Thirty cases of hoarseness appeared or were intensified after surgery and were not caused by RLNP. Eleven cases of postoperative RLNP had no detectable hoarseness. CONCLUSIONS: Besides indirect laryngoscopy, videostroboscopy should be performed in all cases with no evident bilateral normal laryngeal function or normal voice. Otherwise, the incidence of false-positive or false-negative diagnosis of RLNP is likely to be increased.