Tumor neuroectodérmico maligno del tracto gastrointestinal: a propósito de un caso / Malignant neuroectodermal tumor of the gastrointestinal tract: case report

El tumor neuroectodérmico maligno del tracto gastrointestinal es una neoplasia rara con pocos casos reportados en la literatura, especialmente en América Latina. Descrito por primera vez en 2003, se trata de una entidad sin tratamiento estandarizado y de pobre pronóstico. Se presenta el caso de una paciente de 22 años de edad que acude a la consulta por dolor abdominal, anemia y masa abdominal palpable. Luego de estudios pertinentes se decide la conducta resectiva y el posterior tratamiento oncológico. (AU)

Malignant gastrointestinal neuroectodermal tumor (GNET), formerly known as clear cell sarcoma of the gastrointestinal tract, is an extremely rare tumor of mesenchymal origin, which presents great microscopic and molecular similarity to clear cell sarcoma found in other parts of the body, such as tendons and aponeurosis. It is characterized by its rapid evolution, high recurrence rate and frequent diagnosis as metastatic disease.1,2 (AU)

[Malignant gastrointestinal neuroectodermal tumor: a clinicopathological analysis of three cases].

Objective: To investigate the clinicopathological characteristics of malignant gastrointestinal neuroectodermal tumors (GNET), and to describe their clinical, histological, immunophenotypic, ultrastructural, and molecular features, diagnosis and differential diagnosis. Methods: Three cases of malignant GNET were collected at Xijing Hospital of the Fourth Military Medical University, from 2013 to 2022. All patients underwent surgical resection of the tumor. Histological, immunohistochemical (IHC), ultrastructural and molecular genetic analyses were performed, and the patients were followed up for six months, three years and five years. Results: There were two males and one female patients. The tumors were located in the ileum, descending colon, and rectum, respectively. Grossly, the tumors were solid, firm, and poorly circumscribed, measured in size from 2 to 4 cm in greatest dimension, and had a greyish-white cut surface. These tumors were histologically characterized by a sheet-like or nested population of oval to spindled cells or epithelioid cells with weakly eosinophilic or clear cytoplasm, small nucleoli and scattered mitoses. Electron microscopy showed neuroendocrine differentiation, and no evidence of melanogenesis. IHC staining showed that the tumor cells were diffusely positive for S-100 protein, SOX10, CD56, synaptophysin and vimentin. They were negative for melanocytic markers, HMB45 and Melan A. All three cases showed split EWSR1 signals consistent with a chromosomal translocation involving EWSR1. Next-generation sequencing in one case confirmed the presence of EWSR1-ATF1 fusion. These patients were followed up for 6 months, 3 years and 5 years, respectively, and all of them developed possible lung or liver metastases, and one of them died of multiple pulmonary metastases. Conclusion: Malignant GNET has distinctive morphological, IHC, and molecular genetic features and it should be differentiated from other malignancies of the gastrointestinal tract, especially clear cell sarcoma and melanoma.

[Fibrocartilaginous lipoma: a clinicopathological analysis of six cases].

Objective: To investigate the clinicopathological characteristics, immunophenotype, molecular genetics and differential diagnoses of fibrocartilaginous lipomas which consist of adipose tissue, fibrocartilage and fibrous elements. Methods: The clinicopathological features, immunohistochemical profiles and molecular profiles in six cases of fibrocartilaginous lipomas diagnosed at Foshan Traditional Chinese Medicine Hospital, Fudan University Shanghai Cancer Center, the Fifth Affiliated Hospital of Zhengzhou University and the Fourth Affiliated Hospital of Harbin Medical University from January 2017 to February 2022 were included. The follow-up information, diagnosis and differential diagnoses were evaluated. Results: There were three males and three females with a median age of 53 years (range 36-69 years) at presentation. Tumors were located in the extremities, the head and neck region and trunk; and presented as painless masses that were located in the subcutaneous tissue or deep soft tissue. Grossly, three cases were well defined with thin capsule, one case was well circumscribed without capsule, two cases were surrounded by some skeletal muscle. The tumors were composed of fatty tissue with intermingled gray-white area. The tumors ranged from 1.50-5.50 cm (mean 2.92 cm). Microscopically, the hallmark of these lesions was the complex admixture of mature adipocytes, fibrocartilage and fibrous element in varying proportions; the fibrocartilage arranged in a nodular, sheet pattern with some adipocytes inside. Tumor cells had a bland appearance without mitotic activity. Immunohistochemical analysis using antibodies to SMA, desmin, S-100, SOX9, HMGA2, RB1, CD34, adipopholin was performed in six cases; the fibrocartilage was positive for S-100 and SOX9, adipocytes were positive for S-100, adipopholin and HMGA2; CD34 was expressed in the fibroblastic cells, while desmin and SMA were negative. Loss of nuclear RB1 expression was not observed. Other genetic abnormalities had not been found yet in four cases. Follow-up information was available in six cases; there was no recurrence in five, and one patient only underwent biopsy of the mass. Conclusions: Fibrocartilaginous lipoma is a benign lipomatous tumor with mature adipocytes, fibrocartilage and fibrous elements. By immunohistochemistry, they show the expression of fat and cartilage markers. No specific molecular genetics changes have been identified so far. Familiarity with its clinicopathological features helps the distinction from its morphologic mimics.

Malignant gastrointestinal neuroectodermal tumor: A case-based review of literature.

Malignant gastrointestinal (GI) neuroectodermal tumor is an extremely rare entity that was first described by Zambrano et al. in 2003 as "clear cell sarcoma (CCS)-like tumor of the GI tract." It shares some of the histopathological features of CCS but lacks the immunohistochemical (IHC) reactivity for melanocytic markers. Most mesenchymal neoplasms of the GI tract belong to the category of GI stromal tumors and are characterized by the IHC expression of c-KIT. In cases, without detectable KIT receptor expression, several differential diagnoses have to be taken into consideration. In this article, we describe such a case and present a review of all the reported cases till date. We also present the current available knowledge on its pathology and molecular genetics along with the limitations in its diagnosis. Here, we report a case of a 32-year-old man with a tumor of the small bowel composed of polygonal tumor cells arranged in solid nests, alveolar pattern, and pseudopapillary and admixed with numerous osteoclast-like multinucleated giant cells. Immunohistochemically, the tumor cells strongly expressed S-100 protein only. HMB-45, melan-A, CD117, cytokeratin, desmin, smooth muscle actin, and CD-34 were absent. Ki-67 index was 15%. The diagnosis was further confirmed by fluorescence in situ hybridization (FISH) demonstrating the presence of EWSR1 (22q12) translocation. A final diagnosis of malignant gastroneuroectodermal tumor was rendered. The patient is disease-free for 20 months of postsurgery. The diagnosis of this entity should be considered in the presence of S-100-positivity and multinucleated osteoclastic giant cells and the absence of melanocytic differentiation in a tumor arising from GI tract. Further confirmation can be done by performing FISH analysis.

Peripheral Nerve Sheath Tumors in Patients With Neurofibromatosis Type 1: Morphological and Immunohistochemical Study.

BACKGROUND/AIM: The aim of the present investigation was to characterize the growth pattern and antigen profile of peripheral nerve sheath tumors (PNST) in a large series of tumors obtained from patients with Neurofibromatosis type 1 (NF1) focusing on morphological characteristics of diffuse plexiform neurofibroma (DPNF). MATERIALS AND METHODS: Tissue micro-array (TMA) analysis was applied to study 520 formalin-fixed, paraffin-embedded human PNST of 385 patients with confirmed NF1 diagnosis. PNST originated from all areas of the body and were classified as cutaneous neurofibroma (CNF, n=114), diffuse neurofibroma (DNF, n=109), DPNF (n=108), plexiform neurofibroma (PNF, n=110), and malignant peripheral nerve sheath tumor (MPNST, n=22). Histomorphology and antigen expression patterns of the tumors were determined [S100, epithelial membrane antigen (EMA), CD90, mast cell tryptase, and neurofilament]. RESULTS: Benign PNST showed significantly more S100-positive tumor cells than MPNST (p<0.001). EMA expression was most pronounced in perineurium of DPNF. The number of mast cells in CNF, DNF and DPNF was significantly higher compared to PNF and MPNST (p<0.001 for both comparisons, Mann-Whitney U-test). CONCLUSION: DPNF show some distinct cellular characteristics. A high number of EMA positive cells possibly indicates the dissemination of perineural cells to the surrounding tissue. Concerning mast cell density, DPNF resemble DNF and CNS rather than PNF. Close contact of tumor cells in DPNF, DNF and CNF with the immune system is a prerequisite for permanent immunological reactions in contrast to PNF in which tumor cells are partitioned from the immune system by the perineurium and blood-nerve barrier of blood vessels. It is assumed that these morphological distinctions may reflect in part the biological differences between the entities. While PNF is a known precancerous stage in NF1 patients, DPNF are not rated as such. Furthermore, the morphologic differences between benign nerve sheath tumors may be important for the efficacy of drugs to access tumor cells.

RAF1-rearranged spindle cell tumour: report of two additional cases with identification of a novel FMR1-RAF1 fusion.

A subset of spindle cell tumours have been recently identified to harbor recurrent fusion genes, involving NTRK1/2/3, BRAF, RAF1, and RET. The precise classification of these fusion-positive tumours relies essentially on genomic profiling. Herein, we present our experience with two cases of spindle cell tumour which showed RAF1 rearrangement. Both tumours occurred in children with one in the left cheek (case 1) and the other one in the left buttock (case 2). Histologically, case 1 was a low-grade neoplasm characterized by uniform ovoid to short spindle cells showing "patternless" architecture with stromal hyalinization. Case 2 had an overtly malignant phenotype composed of long intersecting fascicles with increased cellularity and mitotic activity. By immunohistochemistry, tumour cells in case 1 showed co-expression of CD34 and S100 protein whereas in case 2 there was only focal staining of CD34 with no expression of S100 protein. Fluorescence in situ hybridization tests using NTRK1/2/3 (case 1 and case 2), ETV6, SS18, BRAF, ROS1, and ALK (case 2) break-apart probes were performed but yielded negative results. Subsequent next-generation sequencing (NGS) demonstrated PDZRN3-RAF1 fusion in case 1 and FMR1-RAF1 fusion in case 2, respectively, which were confirmed by FISH using RAF1 break-apart probe. This study further emphasizes the importance of molecular diagnostics in fusion-positive spindle cell tumours. In addition, we expand the genetic spectrum of RAF1-rearranged spindle cell tumour by describing a novel FMR1-RAF1 fusion gene.

Role of the S100 protein family in liver disease (Review).

Liver disease is a significant health challenge worldwide and comprises liver fibrosis and cirrhosis, viral hepatitis, fatty liver, non­alcoholic fatty liver disease, alcoholic liver disease and hepatocellular carcinoma (HCC). Due to the lack of effective treatments, the prognosis of end­stage liver disease (including advanced liver cirrhosis and HCC) is often poor. S100 proteins are a type of Ca2+ binding protein, which are expressed in a cell­specific manner in vertebrates. These proteins are involved in numerous functions, such as serving as intracellular Ca2+ sensors, transduction of Ca2+ signals and regulation of extracellular factors that affect cellular activity by binding to a range of membrane receptors. Evidence has shown that S100 proteins serve key roles in the occurrence and development of liver disease and can be used as potential therapeutic targets or diagnosis markers. For example, certain studies have suggested that blocking S100 protein expression may be an innovative treatment strategy. The present review focuses on the functions of the S100 protein family in liver disease.

Polymorphous Adenocarcinoma.

Polymorphous adenocarcinoma (PAC) is typically originated from the minor salivary glands and is characterized by cytology uniformity and architectural diversity. PAC commonly harbors PRKD1 E710D mutation. PAC has an excellent prognosis. However, greater than or equal to 10% papillary or greater than or equal to 30% cribriform pattern is an independent adverse prognostic factor. Cribriform adenocarcinoma of salivary gland (CASG) is a controversial entity that is considered within the same histologic spectrum of PAC in current classification schemes; however, it is regarded by some pathologists as a separate entity. CASG shows a propensity to base of tongue location, a lobulated growth pattern, a predominant solid/cribriform architecture, and a high frequency of PRKD1/2/3 fusion.

A case of "ETV6-FISH-negative" secretory carcinoma of the parotid gland: immunohistochemical study.

Secretory carcinoma of the salivary glands is a relatively new disease concept, and is characterized by "morphological resemblance to mammary secretory carcinoma and ETV6-NTRK3 gene fusion." Herein we describe a confusing case and briefly discuss practical diagnostic problems. The patient was a 71-year-old Japanese man who had a tumor consistent with secretory carcinoma at the microscopic and immunohistochemical levels. Immunohistochemically, EMA and S100 protein were noted to be positive along with various cytokeratins as well as mammaglobin and pSTAT5. Moreover, vimentin was focally positive. Smooth muscle actin, p63, p40, and androgen receptor were negative. However, a search using fluorescence in situ hybridization did not reveal a definite split signal for the ETV6 gene. It is presumed that confirming the diagnosis of secretory carcinoma without genetic retrieval will be accepted as a diagnostic method, and we hope that worldwide general recognition may earlier reach "gradual acceptance."

Clinicopathological, immunohistochemical and fluorescence in-situ hybridisation features of early subungual melanoma: an analysis of 65 cases.

AIMS: Very limited data are available concerning the clinicopathological and molecular features of early subungual melanoma (SM), especially with regard to the Asian population. The aim of this study was to investigate the clinical, histological, immunohistochemical and chromosomal features of early SM. METHODS AND RESULTS: Fifty-two in-situ and 13 thin (Breslow thickness ≤1.0 mm) SM cases were retrospectively reviewed. All patients presented with longitudinal melanonychia involving a single digit, and the thumb was the most affected digit (35 of 65, 53.8%). Microscopically, most cases showed small to medium nuclear enlargement (58 of 65) and mild to moderate nuclear atypia (57 of 65). Hyperchromatism and irregular contours of nuclei were persistent features in all cases. The variation of melanocyte count (the number of melanocytes per mm dermal-epithelial junction) ranged from 31 to 255. Intra-epithelial mitoses were identified in 34 cases (52.3%). Statistically, features of in-situ lesions including higher melanocyte count (>70), presence of multinucleated melanocytes, inflammatory infiltrate and cutaneous adnexal extension, were associated with early invasion. Melan-A, human melanoma B (HMB)45, mouse monoclonal melanoma antibody (PNL2) and SOX10 antibodies (>95.0%) showed superior diagnostic sensitivity to S-100 protein (83.1%). Fluorescence in-situ hybridisation (FISH) results were positive in 15 of 23 successfully analysed cases. CONCLUSIONS: To the best of our knowledge, this is the largest single-institution study of early SM in an Asian population, and the largest cohort tested by FISH. Early SM mainly showed small to medium nuclear enlargement and mild to moderate nuclear atypia. High melanocyte count, hyperchromatism and irregular contours of nuclei and intra-epithelial mitoses are crucial diagnostic parameters. Immunohistochemistry, especially SOX10 staining, and FISH analysis are valuable in the diagnosis of SM.

Immunophenotypic Characterization of Germ Cell Tumor-Derived Primitive Neuroectodermal Tumors: Evidence for Frequent Neuronal and/or Glial Differentiation.

CONTEXT.­: Primitive neuroectodermal tumors (PNETs) may arise as a somatic-type malignancy in germ cell tumors. In this setting, most PNETs resemble those of the central nervous system and lack chromosome 22 translocations. However, description of the morphologic and differentiation spectrum of PNETs arising from germ cell tumors is lacking. OBJECTIVE.­: To investigate the morphologic and immunohistochemical features of these tumors, concentrating on neuronal and glial features. DESIGN.­: We selected cases based on a morphologically identifiable glial and/or differentiated neuronal component in association with the undifferentiated PNET. Immunohistochemistry for glial fibrillary acidic protein, S100 protein, synaptophysin, chromogranin A, and SOX11 was performed on tumors with available material, with the scoring of both staining intensity (0-3) and extent (0-3). Thirteen qualifying PNETs of testicular origin with available immunohistochemical stains or stainable material were identified. The complete stain panel was performed in 10 tumors. RESULTS.­: SOX11 demonstrated positive staining in the undifferentiated PNET component of all tumors (10 of 10) and was rarely positive in the differentiated (ie, neuronal/glial) component (1 of 10; focal and weak); synaptophysin was slightly less sensitive in the undifferentiated component (12 of 13; often focal and weak) and also showed positivity in the neuronal/glial component (5 of 13). Glial fibrillary acidic protein and S100 were more frequently positive in the differentiated areas (83% and 77%, respectively) compared with undifferentiated areas (25% and 17%, respectively). CONCLUSIONS.­: SOX11 is a sensitive immunohistochemical marker for testicular PNET, particularly those lacking differentiation. Testicular PNETs often demonstrate glial and/or neuronal differentiation. Differentiation is marked by the acquisition of S100 and glial fibrillary acidic protein expression and SOX11 loss.

Proteomics of exhaled breath condensate in lung cancer and controls using data-independent acquisition (DIA): a pilot study.

Lung cancer, the leading cause of cancer mortality worldwide has a poor prognosis. To develop a non-invasive method for early lung cancer detection, exhaled breath condensate (EBC) was explored in this study. EBC samples were collected from lung cancer patients (n= 10) and healthy controls (n= 10), and a proteomic study was performed to identify potential biomarkers. Data-dependent acquisition was used to build the spectral library, and a data-independent acquisition (DIA) approach was applied for quantification of EBC proteomics. A total of 1151 proteins were identified, and several proteins were significantly upregulated in the lung cancer group compared to the control group. The Gene Ontology analysis revealed that most of the proteins were located within several organelles in the cells and were involved in binding and catalytic activity, and the Kyoto Encyclopedia Genes and Genomes results revealed that the proteins were mainly related to organismal systems and human disease. And S100A11, ANXA1, ENO1, and FABP5 might play a vital role in the EBC proteome. In summary, we demonstrated that the DIA-based quantification method was efficient in performing proteomic analysis in individual EBC samples, and some of the proteins might be novel biomarkers for lung cancer.

Sphingosine 1-Phosphate Receptor 2 Is Central to Maintaining Epidermal Barrier Homeostasis.

The outer layer of the epidermis composes the skin barrier, a sophisticated filter constituted by layers of corneocytes in a lipid matrix. The matrix lipids, especially the ceramide-generated sphingosine 1-phosphate, are the messengers that the skin barrier uses to communicate with the basal layer of the epidermis where replicating keratinocytes are located. Sphingosine 1-phosphate is a bioactive sphingolipid mediator involved in various cellular functions through S1PR1‒5, expressed by keratinocytes. We discovered that the S1pr2 absence is linked to an impairment in the skin barrier function. Although S1pr2-/- mouse skin has no difference in its phenotype and barrier function compared with that of wild-type mouse, after tape stripping, S1pr2-/- mouse showed significantly higher transepidermal water loss and required another 24 hours to normalize their transepidermal water loss levels. Moreover, after epicutaneous Staphylococcus aureus application, impaired S1pr2-/- mouse epidermal barrier function allowed deeper bacterial penetration and denser neutrophil infiltration in the dermis. Microarray and RNA sequence of S1pr2-/- mouse epidermis linked the barrier dysfunction with a decrease in FLG2 and tight junction components. In conclusion, S1pr2-/- mice have compromised skin barrier function and increased bacteria permeability, making them a suitable model for diseases that present similar characteristics, such as atopic dermatitis.

What is hiding behind S100 protein and SOX10 positive oncocytomas? Oncocytic pleomorphic adenoma and myoepithelioma with novel gene fusions in a subset of cases.

Oncocytomas (OCs) in salivary glands are rare benign tumors composed of mitochondria-rich epithelial cells (oncocytes), mostly localized in the parotid gland. The treatment of choice is simple excision. Extensive oncocytic metaplasia of pleomorphic adenoma (PA) and myoepithelioma (ME) can be diagnostically challenging and may camouflage the correct diagnosis. These tumors should be treated more carefully compared with OC, given the risk of frequent recurrences and the possibility of malignant transformation. We have investigated 89 oncocytic lesions from our files, including OC (n = 74) and metaplastic oncocytic variant of PA/ME (n = 15). All OCs were stained for S100 protein and SOX10. The tumors with immunohistochemical expression of one or both markers were tested by next-generation sequencing (NGS). The NGS results were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH). Ten cases originally diagnosed as OC, and 1 low-grade uncertain oncocytic tumor (11/74) revealed nuclear-cytoplasmic and/or nuclear positivity for S100 protein and/or SOX10, respectively. Fusion transcripts CHCHD7-PLAG1 and GEM-PLAG1 were found in 2 cases (1 fusion in each), and these were confirmed by RT-PCR and PLAG1 break-apart FISH probe, respectively. Another 5 cases were positive for PLAG1 rearrangement by FISH. In the control group of 15 oncocytic PA/ME, 4/15 tested tumors harbored gene fusions including NFT3-PLAG1, CHCHD7-PLAG1, FBXO32-PLAG1, and C1orf116-PLAG1 (1 fusion in each case) as detected by NGS. Two fusions were confirmed by RT-PCR, 1 case by FISH, and 1 case was not analyzable by FISH. We additionally tested 24 OCs negative for S100 protein and SOX10 by immunohistochemistry (IHC) and by FISH for rearrangement of PLAG1 gene, but none of them were positive. SOX10 and/or S100 protein immunopositivity in conjunction with rearrangement of the PLAG1 gene assisted in reclassification of a subset of oncocytomas as oncocytic variants of PA and ME. Therefore, we recommend to include S100 protein and SOX10 IHC when diagnosing tumors with predominantly oncocytoma-like differentiation. In addition, by NGS, 3 new gene fusions were detected in oncocytic ME, including NTF3-PLAG1, FBXO32-PLAG1, and GEM-PLAG1, and a new fusion C1orf116-PLAG1 was detected in oncocytic PA.

Rosai-Dorfman Disease-Like Reaction to Tattoo.

A 47-year-old white man presented with a 14-month history of an asymptomatic 2-cm, slow-growing nodular lesion on his left shin that arose in the background of a black tattoo. An excisional biopsy followed by histological examination revealed a prominent lymphohistiocytic infiltrate, with many large, foamy histiocytic cells containing intact inflammatory cells within their cytoplasm, findings consistent with emperipolesis, a feature typical of Rosai-Dorfman disease (RDD). By immunohistochemistry, S-100 (a marker that is positive in almost all cases of RDD) was negative, arguing against the diagnosis of RDD. In addition, prominent black tattoo pigment was seen in many areas, expanding the differential diagnosis to include an unusual reactive lymphohistiocytic response to the tattoo mimicking RDD. Histologically, RDD shows many plasma cells, neutrophils, lymphocytes, and histiocytes with abundant foamy cytoplasm that contains intact lymphocytes and other cells, a phenomenon described as emperipolesis. A wide variety of cutaneous reactions to tattoos have been described, including tenderness, burning pain, inflammation, and pruritus. However, histologic features suggestive of RDD as a reaction to tattoo pigment have not been previously described and should therefore also be considered as a potential rare reaction pattern to tattoos.

Langerhans cell histiocytosis: A great imitator.

Langerhans cell histiocytosis (LCH) is an uncommon but serious inflammatory neoplasia that affects many organs, including the skin. Though uncommon, it should remain high on a clinician's differential diagnosis in treatment-resistant cases of conditions, such as seborrheic dermatitis, diaper dermatitis, arthropod bites, and many more. A thorough history nd physical examination for each patient can aid in the diagnosis; however, if clinically suspicious for LCH, a punch biopsy should be performed. Histologic evaluation of LCH is often enough to differentiate it from the many clinical mimickers. Characteristic findings include a histiocytic infiltrate with "coffee bean"-cleaved nuclei, rounded shape, and eosinophilic cytoplasm. Immunohistochemical stains, including CD1a, S100, and CD207 (langerin) are often needed for a definitive diagnosis. Electron microscopy also demonstrates the ultrastructural presence of Birbeck granules, but this is no longer needed due to immunohistochemical staining. Treatment is often necessary for LCH, if systemic involvement exists.

Mammary analogue secretory carcinoma: A case report.

BACKGROUND: Mammary analogue secretory carcinoma is a rare new entity of low-grade malignant tumor of salivary glands. It shared the same histologic features and the chromosomal translocation t(12;15)(p13;q25) as secretory carcinoma of the breast. AIM: To highlight the diagnosis approaches and the attitude of management in a case of MASC which is the first case reported in Tunisia. Reported case: A case of MASC of the lower left jugal mucosa was reviewed for its microscopic and immunohistochemical features. Fluorescence in situ hybridization (FISH) for the ETV6-NTRK3 translocation was performed. Surgery was the only treatment required in this case. No signs of local or regional recurrence during the one-year follow-up were noticed. COMMENTARIES: Secretory carcinoma was confused with other salivary gland tumors especially acinic cell carcinoma due to their morphological similarities, making diagnosis dilemma. Fluorescence in-situ hybridization (FISH) is the one definitive finding to confirm the diagnosis of MASC and to differentiate it from the other types of salivary gland tumor. At the present time, no specific therapy is available for patients with MASC.

LC/MS/MS-based quantitation of pig and human S100A1 protein in cardiac tissues: Application to gene therapy.

The S100A1 protein is a target of interest for the treatment of heart failure as it has been previously reported to be depleted in failing cardiomyocytes. A gene therapy approach leading to increased expression levels of the protein directly in the heart could potentially lead to restoration of contractile function and improve overall cell survival. S100A1 is a relatively small soluble protein that is extremely well conserved across species with only a single amino acid difference between the sequences in human and pig, a commonly used pre-clinical model for evaluation of efficacy, biodistribution and safety for cardiac-directed gene therapy approaches. This high homology presents a bioanalytical challenge for the accurate detection and quantitation of both endogenous (pig) and exogenous (human) transduced S100A1 proteins post treatment using a human S100A1 gene therapy in pigs. Here we present a sensitive and selective LC-MS/MS approach that can easily differentiate and simultaneously quantitate both human and pig S100A1 proteins. Additionally, we report on a detailed profiling of S100A1 protein in various pig tissues, a comprehensive evaluation of S100A1 distribution in pig hearts and a comparison to S100A1 levels in human cardiac samples.