Aim: To investigate co-expression of ATRX and HIF-1α in kidney neoplasm in relation to its origin. Introduction: A heterogenous group of kidney tumors is believed to arise from a variety of specialized cells along the nephron – proximal tubules [Clear cell Renal Cell carcinoma (ccRCC) and papillary RCC (pRCC)] and collecting tubules [chromophobe RCC (chRCC) and oncocytoma]. ATP-dependent helicase (ATRX) is a chromatin remodeling protein involved in gene regulation and aberrant DNA methylation during cancerogenesis. Activation of hypoxia inducible factor (HIF-1α) is an early event in most RCC following inactivation of the VHL tumor suppressor gene. Material and Methods: A total of 46 kidney tumors (n=33 ccRCC, n=1 mRCC, n=4 pRCC, n=5 chRCC and n=3 oncocytomas) was immunohistochemically analyzed for ATRX and HIF-1α expression. Results: Diffuse and focal positivity of ATRX expression was found in 51.5% of ccRCC, while 54.5% had HIF-1α positivity. Co-expression of ATRX/HIF-1α was not related to nuclear grade and stage of ccRCC. Metastatic ccRCC had strong expression of both markers. pRCC type II showed weak ATRX/HIF-1α expression, while pRCC type I was negative for both markers. Interestingly, all analyzed oncocytomas and chromophobe RCC were negative for ATRX/HIF-1α. Conclusion: Our results suggest that signaling pathways have different patterns of activation/suppression of ATRX/HIF-1α in oncocytomas and chRCC compared to other RCC types. Downregulation or loss of ATRX/HIF-1α coexpression in benign tumors should be further investigated in order to determinate mechanisms of ATRX/ HIF-1α signaling transport renal neoplasm with different origin.

Aim: The aim of the study is to classify tumors into four main molecular subtypes using immunohistochemistry and in situ hybridisation methods, as well as to determine frequency of different carcinoma subtypes. Introduction: Four molecular subtypes of breast carcinoma can be identified: Luminal A and Luminal B (hormone receptors positive), HER2 enriched (HER2 overexpression) and Triple Negative / Basal-like (absence of HER2 amplification and steroid receptors expression). Materials and Methods: Cross-sectional study, conducted in Institute of pathology, Medical Faculty, University in Belgrade, during the ten months period in 2017, included 337 patients with diagnosed breast carcinoma. Using the methods of immunohistochemistry, all four markers (estrogen, progesteron, HER2, and Ki67) were evaluated on breast carcinoma tissues. As additional methods, “in situ” hybridisation (FISH, SISH) was used in cases if HER2 oncoprotein results on immunohistochemistry were equivocal. Results: Luminal A, Luminal B, HER2 enriched, and Triple Negative carcinomas were present in 133 (39,45%), 147 (43,62%), 22 (6,5%), 34 (10,08%) cases, respectively. For 55 (16,35%) cases, in situ hybridisation had been done in order to classify carcinomas in proper molecular subtype. Conclusion: Frequency of molecular subtypes of breast carcinomas in our study are similar to literature data for European countries. Breast carcinoma subtyping has prognostic and predictive values for further patient treatment, and should be done in institutions with adequately trained personnel and equipment, in order to achive best results in the shortest time.

Aim: Report of two cases of benign skin tumors of different histogenesis with anaplastic lymphoma kinase (ALK) gene rearrangement. Introduction: ALK gene mutation or rearrangement positive tumors (ALKomas) are heterogeneous group in which such genetic finding has diagnostic or predictive value. ALK gene fusions are associated with tumorigenesis of some cutaneous tumors, e.g. plexiform Spitz nevus (PSN) and epithelioid fibrous histiocytoma (EFH). Cases reports: Histological, immunohistochemical (IHC) and genetic characteristics were analyzed in two skin tumors with ALK gene rearrangement proved by fluorescent in situ hybridization (FISH). First case is PSN localized on face in a 8-year-old boy. Tumor was consisted of spindle cells arranged in plexiform growth pattern throughout epidermis and dermis, with following IHC characteristics: HMB45  focally, p16 , Ki67  in 1% of cells. Deletion of CDKN2A gene was not detected in significant number, while ALK gene rearrangement was positive in 37/50 (74,2%) of cells. Second case is EFH localized on shoulder in a 16-year-old girl. This dermal based tumor was consisted of tightly packed large epithelioid cells, which were CD68 , p16 , S100-, HMB45-, SOX10-, CD1a-, Ki67 (<5% of cells). ALK gene rearrangement was positive in 24/100 (24%) of cells, and focal chromosome 2 polysomy was noted. Neither mitoses nor necrosis were present in any of presented cases. Conclusion: Skin ALKomas are tumors with heterogeneous histological and immunohistochemical characteristics, and also with variable extent of ALK rearrangement.

Aim: To examine the quality of tested lung carcinoma samples, frequency and type of EGFR mutations, and their correlation with patients clinical characteristics (gender, age, smoking habits, clinical stage). Introduction: Mutations in Epidermal Growth Factor Receptor (EGFR) have a role in lung carcinoma development and they are more prevalent in women and non-smokers. Evaluation of EGFR mutations in lung carcinomas in mandatory for targeted therapy with tyrosine kinase inhibitors. Test performance depends on the quality of tested samples and a test type. Material and Methods: We evaluated reports of EGFR mutation real-time PCR analyses in lung carcinoma samples performed from June 2017 till February 2018. Presence of mutations was correlated with clinical characteristics of lung carcinoma patients. Results: A total of 341 samples was received for testing, among which 40 (11.7%) was unsuitable for analysis due to a low tumor cell content (<5%). Three types of mutations were detected in a total of 24 (8%) cases: L858R in 12 (50%) cases, exon 19 deletion in 10 (41.7%) cases, and G719A/C/S in two cases (8.3%). Mutations were more prevalent in women (13.7%) then in men (4.3%) (p=0.004). Patients with EGFR mutated tumors were older (67,6ą9,4 years), compared to those with non-mutated tumors (62,3ą8,8 years) (p=0,003). Smoking habits and clinical stage were not associated with mutation status in lung carcinomas. Mutations were detected only in adenocarcinomas. Conclusion: Our results suggest the low frequency of EGFR mutations in tested patients, but they are more prevalent in women and older patients.

Aim: We present the case of a rare localization of the alveolar soft part of the sarcoma in the visceral organ. Introduction: Alveolar soft part sarcoma (ASPS) is a rare mesenchymal tumor typically occurring in young patients, more frequently in females. Common localization of ASPS is skeletal musculature of lower extremities. ASPS in visceral organs usually represents a metastasis from the more common primary location in skeletal muscles. ASPS is characterized by a tumor-specific translocation which causes the fusion of the TEF3 with a ASPL gene (also known as ASPSCR1). Case report: Female 47 years old was admitted to hospital due to abdominal pain. Urgent surgery was performed due to ileus. Ileal tumor was detected intraoperatively as a cause of ileus. Tumor was infiltrated whole intestinal circumference, with dimension 70mm x 47cm and evident perforation. Histology showed well-defined nests of pleomorphic cells separated by delicate fibrovascular septae. Within described nests there is a prominent lack of cellular cohesion, representing for the distinctive pseudoalveolar pattern. Immunohistochemical stadies were diffusely positive for TFE3 and focally positive for CD34 and alpha-SMA and negative for panCK, DOG-1, CD117, S-100, HMB45, Desmin. Immunopositivity for Ki67 was present in 20% of tumor cells. FISH analysis was done using locus specific dual color break-apart TFE3 (3 and 5 ) probe and rearrangement in the TFE3 gene was confirmed. Conclusion: Despite the fact that ASPS is rare mesenchymal tumor in visceral organs it have to be considered as possible diagnosis especially in cases with typical histological features and immunohistochemical profile. Definitive diagnosis of ASPS must be confirmed by FISH analysis.