Development of Multidrug Resistance in Acute Myeloid Leukemia Is Associated with Alterations of the LPHN1/GAL-9/TIM-3 Signaling Pathway.

P-glycoprotein (known as ABCB1 transporter) expression in myeloid blasts of acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) leads to the commonly observed multidrug resistance. Overexpression of latrophilin-1 was detected in leukemic cells from AML patients. In a previous study, we showed that ABCB1 overexpression is associated with decreased latrophilin-1 expression in MOLM-13/VCR and SKM-1/VCR AML cell variants derived from MOLM-13 and SKM-1 cells by vincristine selection/adaptation. In the present study, we found that if ABCB1 overexpression occurs in myeloid blasts of newly diagnosed MDS patients, latrophilin-1 expression is attenuated. Latrophilin-1 may initiate TIM-3- and galectin-9-mediated immune escape. We demonstrated changes in the expression of both proteins by comparing ABCB1-positive cell variants (MOLM-13/VCR, SKM-1/VCR) with their ABCB1-negative counterparts. Galectin-9 was present in our cell lines in eight protein isoforms for which we identified the respective transcription variants resulting from alternative splicing, and we verified their structure by sequencing. The isoform profile of galectin-9 was different between ABCB1-positive and ABCB1-negative cell variants. The interaction partner of galectin-9 is CD44, and its expression was altered in the ABCB1-positive variants MOLM-13/VCR and SKM-1/VCR compared to their ABCB1-negative counterparts.

Immunohistochemical evaluation of potential molecular targets of desmoid-type fibromatosis.

Desmoid-type fibromatosis is locally aggressive tumor rare in general population, although commonly present in patients with familial adenomatous polyposis, significantly contributing to the morbidity and mortality of patients. To optimize and individualize the management of patients it is necessary to better understand the biology of these tumors. Immunohistochemical analysis of ß-catenin, VEGF, hormone receptors ERß, ERα and PR, COX-2, APC protein, EGFR, c-kit (CD117), bcl-2 and HER2 expression, potential therapeutic targets, was carried out on 15 archival biopsy samples together with APC gene mutational screening. ß-catenin expression was found in all samples, with over 73% showing high range positivity, however with no prognostic significance. Non-specific cytoplasmic localization of ß-catenin was observed FAP-associated cases lacking CTNNB1 mutations. Hormone receptor status demonstrated expression of ERß in 93% of lesions, without detectable ERα or PR. Distinct COX-2 expression of variable intensity was present in all but one desmoid-type fibromatosis case. All lesions demonstrated intense VEGF positivity. Immunoreactivity for the APC protein was found only in 4 cases associated with FAP. No EGFR, HER2, bcl-2 or c-kit expression was detected in any sample. Expression of ß-catenin, VEGF, ERß, COX-2 in high number of cases suggests a potential as future therapeutic targets in desmoid-type fibromatosis.

Perivascular Epithelioid Cell Tumor (PEComa) of the Uterine Cervix: A Case Report of a 43-Yr-Old Woman With Abnormal Uterine Bleeding Treated With Hysterectomy.

Perivascular epithelioid cell tumor (PEComas) are a group of ubiquitous neoplasms described in different organs that share distinctive morphologic, immunohistochemical, ultrastructural, and genetic features. They have been reported in several organs such as the uterus, lung, kidney, liver, small and large bowel, and prostate. To the best of our knowledge, only 8 cervical PEComa cases have been described. We report the case of a 43-yr-old woman who presented with abnormal uterine bleeding. Clinical diagnosis of a malignant cervical lesion followed an excision, histopathologically evaluated as PEComa. The hysterectomy specimen confirmed the diagnosis by strong HMB-45 positivity, weak S100 positivity, and focal, moderate cytoplasmic TTF-1 positivity, and negative melan A, SMA, desmin, vimentin, cytokeratins, CD1a and other markers. The patient was negative for tuberous sclerosis complex, did not receive additional therapy, and 3 yr later is disease free. Cervical PEComas are very rare tumors but have to be considered in the differential diagnosis of cervical lesions exhibiting unusual cytologic and immunohistochemical characteristics.

[Von Hippel-Lindau syndrome - two sides of the same coin]. / Von Hippelov-Lindauov syndróm - dve strany jednej mince.

Von Hippel-Lindau syndrome (VHL) is a rare genetic disease. Its incidence is 1 : 36,000, there is the familial occurrence in 80 % of cases , the remaining cases are de novo mutations. The disease is caused by the highly penetrant mutations in the VHL gene (3p25.3) and is characterized by the occurrence of benign and malignant neoplasms. The most common VHL tumors are the tumors of the retina, brain and spinal hemangioblastomas, renal cell carcinoma, pheochromocytoma, endolymfatic sac tumors and pancreatic tumors and cysts. The mean age of the VHL patients during the diagnosis is 20-40 years. The diagnosis can be confirmed by a positive family history and the presence of one of the typical tumor. In case of no family history, the diagnosis has to be assessed by the presence of the multiple tumors. The clinical signs and prognosis of VHL depend on the location and extent of the tumors. The life expectancy is 50 years. The most common causes of death are complications of the renal cancer and the brain tumors. The treatment requires a multidisciplinary collaboration through the whole life of patients. This 2 cases report we demonstrate the differences among the patients with de novo mutations disease and the patient with familial incidence.Key words: pheochromocytoma - renal cell carcinoma - von Hippel-Lindau syndrome.

Incidence of common preleukemic gene fusions in umbilical cord blood in Slovak population.

The first event in origination of many childhood leukemias is likely the presence of preleukemic clone (transformed hematopoietic stem/progenitor cells with preleukemic gene fusions (PGF)) in newborn. Thus, the screening of umbilical cord blood (UCB) for PGF may be of high importance for developing strategies for childhood leukemia prevention and treatment. However, the data on incidence of PGF in UCB are contradictive. We have compared multiplex polymerase chain reaction (PCR) and real-time quantitative PCR (RT qPCR) in neonates from Slovak National Birth Cohort. According to multiplex PCR, all 135 screened samples were negative for the most frequent PGF of B-lineage acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). To explore the prevalence of prognostically important TEL-AML1, MLL-AF4 and BCR-ABL (p190), 200 UCB were screened using RT qPCR. The initial screening showed an unexpectedly high incidence of studied PGF. The validation of selected samples in two laboratories confirmed approximately » of UCB positive, resulting in ∼4% incidence of TEL-AML1, ∼6.25% incidence of BCR-ABL1 p190, and ∼0.75% frequency of MLL-AF4. In most cases, the PGF presented at very low level, about 1-5 copies per 105 cells. We hypothesize that low PGF numbers reflect their relatively late origin and are likely to be eliminated in further development while higher number of PGF reflects earlier origination and may represent higher risk for leukemia.