ARID1B, a member of the human SWI/SNF chromatin remodeling complex, exhibits tumour-suppressor activities in pancreatic cancer cell lines.

BACKGROUND: The human ATP-dependent SWItch/sucrose nonfermentable (SWI/SNF) complex functions as a primary chromatin remodeler during ontogeny, as well as in adult life. Several components of the complex have been suggested to function as important regulators of tumorigenesis in various cancers. In the current study, we have characterised a possible tumour suppressor role for the largest subunit of the complex, namely the AT-rich interaction domain 1B (ARID1B). METHODS: We performed Azacytidine and Trichostatin A treatments, followed by bisulphite sequencing to determine the possible DNA methylation-induced transcription repression of the gene in pancreatic cancer (PaCa) cell lines. Functional characterisation of effect of ARID1B ectopic expression in MiaPaCa2 PaCa cell line, which harboured ARID1B homozygous deletion, was carried out. Finally, we evaluated ARID1B protein expression in pancreatic tumour samples using immunohistochemistry on a tissue microarray. RESULTS: ARID1B was transcriptionally repressed due to promoter hypermethylation, and ectopic expression severely compromised the ability of MiaPaCa2 cells to form colonies in liquid culture and soft agar. In addition, ARID1B exhibited significantly reduced/loss of expression in PaCa tissue, especially in samples from advanced-stage tumours, when compared with normal pancreas. CONCLUSION: The results therefore suggest a possible tumour-suppressor function for ARID1B in PaCa, thus adding to the growing list of SWI/SNF components with a similar function. Given the urgent need to design efficient targeted therapies for PaCa, our study assumes significance.

Isolated Rosai Dorfman disease of the central nervous system presenting as dural-based and intraparenchymal lesions.

OBJECTIVE: To report three patients with isolated Rosai Dorfman disease of the central nervous system. CASE REPORTS: We report two patients with dural-based lesions diagnosed imageologically as meningiomas, and one patient with multiple intraparenchymal lesions diagnosed imageologically as lymphoma. Two patients were males and one was female. All were above 35 years of age with no nodal or other system involvement. The diagnosis was established on surgically excised masses during histopathology. One patient died due to unrelated causes 10 years later and the other two are symptom-free at 21.5- and 11.5-year-follow-up. CONCLUSIONS: Awareness of the entity and consideration in the differential diagnosis of dural-based/intraparenchymal lesions is necessary for diagnosis and prognosis.

Spectrum of malignancies in human immunodeficiency virus - positive patients at a Tertiary Care Centre in South India.

CONTEXT: India has a very large number of patients living with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome. Opportunistic infections in these patients are commonly encountered. However, malignancies in such patients also do occur. AIM: The aim was to study the spectrum of malignancies in HIV-positive patients at a tertiary health care center. SETTINGS AND DESIGN: Retrospective study. MATERIALS AND METHODS: The cases were retrieved from pathology record files at our Institute from January 2003 to December 2008. The follow-up was obtained from Medical oncology records. The morphology of each case was reviewed along with immunohistochemistry wherever done. RESULTS: There were 61 such cases (51 males, 10 females). The age range was 7-78 years with a median of 35 years. The clinical presentation varied according to the malignancy. The largest group was non-Hodgkin lymphoma (18 nodal, 23 extra-nodal). The others included carcinoma breast (4), chronic myeloid leukemia (3), Burkitt Leukemia (2), squamous cell carcinoma anal region (2), multiple myeloma (2) and one each of miscellaneous malignancies (7). CONCLUSION: Malignancies in HIV positive individual occurred in younger individuals. Non-Hodgkin lymphomas, especially extra-nodal lymphomas, were the most common malignancy. There were no cases of proven Kaposi's sarcoma or invasive cervical carcinomas. There were two cases of multiple myeloma which are infrequently reported.

Intraoperative cytology (squash smear) in neurosurgical practice - pitfalls in diagnosis experience based on 3057 samples from a single institution.

OBJECTIVES: The smear technique is challenging for a neuropathologist where rapid and accurate diagnosis is to be given on small biopsies. The present study, a large retrospective analysis of squash smears in neurosurgical practice, was conducted to assess the usefulness, accuracy and the diagnostic pitfalls of smear diagnosis. METHODS: The authors analysed 3057 central nervous system (CNS) lesions sent for intraoperative cytology (IC) during the years 1988-2005. The stain used was 1% alcoholic toluidine blue. The smear diagnosis was compared with the histological diagnosis to evaluate the diagnostic accuracy. RESULTS: Diagnostic accuracy irrespective of lesion and site ranged from 83.0% to 86.0% per year (mean=85%). The highest rate of correlation among common brain tumours was noted in schwannoma (96.6%) and pituitary adenoma (92.2%), followed by meningiomas (88.9%), astrocytomas (88.4%), chordomas (86.4%) and neurocytomas (86.9%). Infections as a whole contributed 380 cases. The most common infection was tuberculosis. CONCLUSION: This is the largest series reported from India to the best of our knowledge. Squash smear technique is a very reliable and rapid method of intraoperative diagnosis. Knowledge of clinical and neuroimaging details helps the experienced neuropathologist to improve the diagnostic accuracy.