MicroRNA-7 Regulates Migration and Chemoresistance in Non-Hodgkin Lymphoma Cells Through Regulation of KLF4 and YY1.

The discovery and description of the role of microRNAs has become very important, specifically due to their participation in the regulation of proteins and transcription factors involved in the development of cancer. microRNA-7 (miR-7) has been described as a negative regulator of several proteins involved in cancer, such as YY1 and KLF4. We have recently reported that YY1 and KLF4 play a role in non-Hodgkin lymphoma (NHL) and that the expression of KLF4 is regulated by YY1. Therefore, in this study we analyzed the role of miR-7 in NHL through the negative regulation of YY1 and KLF4. qRT-PCR showed that there is an inverse expression of miR-7 in relation to the expression of YY1 and KLF4 in B-NHL cell lines. The possible regulation of YY1 and KLF4 by miR-7 was analyzed using the constitutive expression or inhibition of miR-7, as well as using reporter plasmids containing the 3 'UTR region of YY1 or KLF4. The role of miR-7 in NHL, through the negative regulation of YY1 and KLF4 was determined by chemoresistance and migration assays. We corroborated our results in cell lines, in a TMA from NHL patients including DLBCL and follicular lymphoma subtypes, in where we analyzed miR-7 by ISH and YY1 and KLF4 using IHC. All tumors expressing miR-7 showed a negative correlation with YY1 and KLF4 expression. In addition, expression of miR-7 was analyzed using the GEO Database; miR-7 downregulated expression was associated with pour overall-survival. Our results show for the first time that miR-7 is implicate in the cell migration and chemoresistance in NHL, through the negative regulation of YY1 and KLF4. That also support the evidence that YY1 and KLF4 can be a potential therapeutic target in NHL.

Tumors of the salivary gland in Mexicans. A retrospective study of 360 cases.

OBJECTIVE: To establish distribution frequency and demographic characteristics of salivary gland tumours (SGT) in order to identify possible risk profiles. DESIGN OF STUDY: The present report constitutes an eight year retrospective study (January 2000-August 2007). The archives of the Clinical and Experimental Pathology Laboratory (Graduate and Research Division, Dental School, National Autonomous University of Mexico) as well as archives of the Surgical Pathology Service (General Hospital, Mexico City) were subject to revision in order to select all cases where SGT tumour diagnoses were emitted. Age and gender of patients as well as SGT topography were obtained from medical records. Selected cases were classified according to location of the lesion, histological lineage and biological behaviour. RESULTS: 360 cases of SGT were included, 227 (67%) cases were benign tumours, while 83 cases (23%) were malignant tumours. SGT were most frequent in women with ages ranging from their 3rd to 5th decades of life. 275 tumours were located in major salivary glands, 78.9% of them were identified in the parotid gland. The most frequent location of tumours arising from minor salivary glands (33 cases, 38%) was found in the palatine glands. Tumours of epithelial lineage were the predominant histological type. The most frequent benign tumours were pleomorphic adenomas (86.1%) and papillary cystadenoma lymphomatosum (7.3%). The most frequent malignant tumours were adenoid cystic carcinomas (25%) and mucoepidermoid carcinomas (23.6%). CONCLUSIONS: Salivary gland tumours in Mexican population appear principally in major salivary glands of women in their 3rd to 5th decade of life.

[Enamel hypoplasia in tuberous sclerosis]. / La hipoplasia del esmalte en la esclerosis tuberosa.

Dental enamel hypoplasia is a constant and pathognomonic sign in patients with TS. The defect consists in small cavities (pits) that measure average 80 microns and affect only the enamel without producing lesion to the dentin. We studied the morphology of retained dental pieces of three patients with TS. The pits showed conical and cylindrical shape and measured from 50 to 500 microns. The identification of enamel hypoplasia in deciduous and permanent teeth is of a great value for early diagnosis when other anomalies of TS are not yet produced.

[Atypical biological behavior of alveolar rhabdomyosarcoma in five patients]. / Comportamiento biológico atípico del rabdomiosarcoma alveolar en cinco pacientes.

Five cases of alveolar rhabdomyosarcoma with atypical clinical features are reported. Three patients showed lymphadenopathy as the first clinical manifestation, mimicking a lymphoma or a non identified primary tumor with lymph node metastases. One patient presented systemic neoplastic disease and two had the primary tumor in atypical locations, such as the mediastinum and retroperitoneum. All patients died and in four of them an autopsy was performed. The histological diagnosis was confirmed by immunohistochemical studies on four cases. The alveolar rhabdomyosarcoma has a poor prognosis and can have a variable clinical presentation and morphology, simulating lymphomas, leukemias and systemic metastatic disease with an unknown primary neoplasm, such as in the cases here in reported.