Sandhya Sundaram

Morphology to morphometry in cytological evaluation of thyroid lesions

Aim: To evaluate the cytomorphometric features in fine needle aspiration cytology (FNAC) of thyroid lesions. Materials and Methods: FNAC of 36 thyroid cases was reviewed. The study included 10 cases each of follicular lesion, adenomatous goiter, papillary carcinoma, 4 cases of medullary carcinoma and 2 cases of anaplastic carcinoma. Their ages ranged from 28 to 50 years, and there were nine females and one male. Morphometric analysis was done on aspiration smears from 36 thyroid lesions. Hematoxylin and Eosin stained smears were examined using image analyzer Proplus V software. Morphological parameters measured included mean nuclear diameter, mean nuclear perimeter, mean nuclear area, circular rate, largest to smallest dimension ratio (LS ratio) and coefficient of variation of nuclear area (NACV). Statistical Analysis: Statistical evaluation was carried out using the analysis of variance (ANOVA) test for the five variables, both within the group and in between the groups. The result was considered significant when P < 0.05. Results: The follicular carcinomas had higher LS ratio than patients with adenomatous goiters. Mean nuclear diameter and the mean nuclear perimeter were higher in anaplastic carcinomas when compared to other subtypes and were the least for follicular neoplasms. Conclusion: When correctly applied, quantitative estimation of cytological nuclear features can play an important role in preoperative assessment and can complement morphological features in thyroid lesions.

Coronary atherosclerosis in sudden cardiac death: an autopsy study.

BACKGROUND The incidence of ischemic heart disease (IHD) has markedly increased in India over the past few years. Considering the variations in racial, dietary and lifestyle patterns in our population, it is essential to study the biology of coronary atherosclerosis in our patients. Vulnerable plaques have a large number of foam cells, extracellular lipid, thin fibrous caps and clusters of inflammatory cells and are more prone to rupture. These plaques are nourished by the microvessels arising from the vasa vasorum of the blood vessels and by lumen-derived microvessels through the fibrous cap. This autopsy study was designed to analyse the coronary arterial tree in cases of sudden cardiac death, classify coronary atherosclerotic plaques and to assess the factors contributing to vulnerability of the plaques including inflammation, calcification and microvascular density. MATERIALS AND METHODS Seven cases of sudden cardiac death were included in the study. The hearts were perfusion-fixed and the coronary arteries along with their main branches were dissected and studied. The location of the plaques, type of plaques, presence of inflammation and calcification were assessed. The cap thickness and microvessel density per 1000 um 2 were assessed. The statistical significance was estimated. RESULTS AND CONCLUSIONS Extensive high-grade coronary atherosclerotic disease was seen in all sudden cardiac death cases. Majority of the plaques were vulnerable. High-grade inflammation was seen in most of the vulnerable and ruptured plaques. All the ruptured plaques were uncalcified indicating that calcification probably stabilizes the plaques and protects against rupture. Increased microvessel density was noted in ruptured plaques compared to vulnerable plaques. However, it was not statistically significant.

P21-activated kinase 1 (Pak1) signaling influences therapeutic outcome in pancreatic cancer

BACKGROUND Therapeutic resistance to gemcitabine in pancreatic ductal adenocarcinoma (PDAC) is attributed to various cellular mechanisms and signaling molecules that influence as a single factor or in combination. DESIGN In this study, utilizing in vitro p21-activated kinase 1 (Pak1) overexpression and knockdown cell line models along with in vivo athymic mouse tumor xenograft models and clinical samples, we demonstrate that Pak1 is a crucial signaling kinase in gemcitabine resistance. RESULTS Pak1 kindles resistance via modulation of epithelial-mesenchymal transition and activation of pancreatic stellate cells. Our results from gemcitabine-resistant and -sensitive cell line models showed that elevated Pak1 kinase activity is required to confer gemcitabine resistance. This was substantiated by elevated levels of phosphorylated Pak1 and ribonucleotide reductase M1 levels in the majority of human PDAC tumors when compared with normal. Delineation of the signaling pathway revealed that Pak1 confers resistance to gemcitabine by preventing DNA damage, inhibiting apoptosis and regulating survival signals via NF-κB. Furthermore, we found that Pak1 is an upstream interacting substrate of transforming growth factor β-activated kinase 1-a molecule implicated in gemcitabine resistance. Molecular mechanistic studies revealed that gemcitabine docks with the active site of Pak1; furthermore, gemcitabine treatment induces Pak1 kinase activity both in vivo and in cell-free system. Finally, results from athymic mouse tumor models illustrated that Pak1 inhibition by IPA-3 enhances the cytotoxicity of gemcitabine and brings about pancreatic tumor regression. CONCLUSION To our knowledge, this is the first study illustrating the mechanistic role of Pak1 in causing gemcitabine resistance via multiple signaling crosstalks, and hence Pak1-specific inhibitors will prove to be a better adjuvant with existing chemotherapy modality for PDAC.

Malignant proliferating trichilemmal tumour presenting early in life: An uncommon feature

Malignant proliferating trichilemmal tumour is a rare cutaneous malignant neoplasm usually occurring in elderly women. We present a case of malignant trichilemmal tumour in a young lady of 26 years of age with a previous history of proliferating trichilemmal tumour at the same site.

Epstein-Barr virus positive B-cell lymphoproliferative disorder/polymorphous B-cell lymphoma of the urinary bladder: A case report with review of literature

We report an unusual case of a localized Epstein-Barr virus (EBV)-positive B cell lymphoproliferative disorder (LPD)/polymorphous B cell lymphoma of the urinary bladder in a 67 years old female patient. She had no known predisposing immunodeficiencies and presented with recent onset of hematuria. The CT and cystoscopic examination revealed a localized 2.5 cm polypoid or plaque-like mucosal mass on the right posterior and lateral wall of the bladder. The biopsy sample showed a diffuse and densely polymorphous atypical lymphoid infiltrate admixed with numerous small lymphocytes, histiocytes and occasional plasma cells and neutrophils. The large atypical cells were CD20+, CD79a+, CD30+, CD43+ and they were strongly positive for EBV by in situ hybridization using anti-EBER-1 probe. Polymerase chain reaction (PCR) for immunoglobulin heavy chain gene rearrangement study showed a clonal gene rearrangement. The findings indicated EBV+LPD of the bladder. Primary lymphoma of bladder is rare and primary EBV+LPD of the bladder has not been previously described. Potential misdiagnosis of poorly differentiated urothelial carcinoma can occur and accurate diagnosis depends on comprehensive immunohistochemical and molecular workups.

Biological behavior of preneoplastic conditions of the endometrium: A retrospective 16-year study in south India

Background: The biological behavior of endometrial carcinoma differs in epidemiology, presentation, and prognosis, suggesting that there are two fundamentally different pathogenic types of disease: type I (estrogen related, endometrioid type) and type II (non-estrogen related, non-endometrioid type). Untreated hyperplasia can develop into an endometrioid type of adenocarcinoma, hence, it is important to recognize the former type. In contrast to cervical cancers, there are limited studies with respect to the biology of hyperplastic lesions documented from India. This was a 16-year retrospective study, carried out to determine the nature and outcome of proliferative lesions of the endometrium in a referral center from south India. Materials and Methods: A histopathological diagnosis of the endometrial hyperplasia, polyp, and carcinoma, on endometrial biopsy and hysterectomy specimens, over a 16 year period (1983 to 1999), were recorded in a computer and the case slides were reviewed. Using the computer software Foxpro, the patients who had come more than once for a subsequent or previous biopsy were identified. An attempt was made to look for progression, regression or a static nature of the lesion in the follow-up cases. Results: A total of 1778 cases were studied, and only 74 patients with endometrial hyperplasia and five cases of benign endometrial polyp had follow-up endometrial histopathology. Hyperplasia cases included 59 cases of simple hyperplasia, 10 cases of complex hyperplasia without atypia, and five cases with atypia. The predominant age for patients with all types of hyperplasias was 41 – 50 years. Progression to a higher grade was seen in 8.10%, regression to a lower grade was seen in 9.45%, lesions reverted to a normal pattern in 10.81% cases, and lesions persisted in 70.27% of the cases. A mixed pattern was seen in 54 cases, with predominant coexistent lesion being simple and complex hyperplasia without atypia. Conclusion: The fate of the hyperplastic lesion of the endometrium showed a varied pattern. Follow-up cases predominantly showed persistence of the lesion, possibly resulting from a fluctuating but higher level of estrogenic stimulus. Hence, it was not only the high levels of estrogen that influenced the biology, but its sustenance for a prolonged period.

Threonine 209 phosphorylation on RUNX3 by Pak1 is a molecular switch for its dualistic functions

P21 Activated Kinase 1 (Pak1), an oncogenic serine/threonine kinase, is known to have a significant role in the regulation of cytoskeleton and cellular morphology. Runx3 was initially known for its role in tumor suppressor function, but recent studies have reported the oncogenic role of Runx3 in various cancers. However, the mechanism that controls the paradoxical functions of Runx3 still remains unclear. In this study, we show that Runx3 is a physiologically interacting substrate of Pak1. We identified the site of phosphorylation in Runx3 as Threonine 209 by mass spectrometry analysis and site-directed mutagenesis, and further confirmed the same with a site-specific antibody. Results from our functional studies showed that Threonine 209 phosphorylation in Runx3 alters its subcellular localization by protein mislocalization from the nucleus to the cytoplasm and subsequently converses its biological functions. This was further supported by in vivo tumor xenograft studies in nude mouse models which clearly demonstrated that PANC-28 cells transfected with the Runx3-T209E clone showed high tumorigenic potential as compared with other clones. Our results from clinical samples also suggest that Threonine 209 phosphorylation by Pak1 could be a potential therapeutic target and of great clinical relevance with implications for Runx3 inactivation in cancer cells where Runx3 is known to be oncogenic. The findings presented in this study provide evidence of Runx3-Threonine 209 phosphorylation as a molecular switch in dictating the tissue-specific dualistic functions of Runx3 for the first time.

UnPAKing RUNX3 functions-Both sides of the coin.

ABSTRACT Post translational modifications of RUNX3 have been shown to play an important role in directing RUNX3 functions. In this review we highlight the phosphorylation dependent functions of RUNX3 as regulated by PAK1 and its implications on tumorigenesis.

KIBRA attains oncogenic activity by repressing RASSF1A

Background:KIBRA—initially identified as a neuronal associated protein is now shown to be functionally associated with other tissue types as well. KIBRA interacts with dyenin light chain 1 and this interaction is essential for oestrogen receptor transactivation in breast cancer cells. KIBRA as a substrate of Cdk1, Aurora kinase and ERK plays an important role in regulating cell cycle, cell proliferation and migration. Despite these evidences, the exact role of KIBRA in cancer progression is not known.Methods:We studied the expression of KIBRA in breast tissues and breast cancer cell lines by western blotting, immunohistochemisry (IHC) and RT-PCR. Stable over expression and knockdown clones were generated to study the transforming properties of KIBRA by conventional assays. Xenograft studies were performed in nude mice to study the in vivo tumourigenic efficacy of KIBRA. qPCR array was performed to understand the molecular mechanism behind oncogenic activity of KIBRA.Results:Our results showed that KIBRA is upregulated in breast cancer cells and in malignant human breast tumours by both western blotting and IHC. Interestingly, we found that KIBRA expression level goes up with increase in breast cancer progression in well-established MCF10A model system. Further, results from stable overexpression clones of KIBRA in fibroblasts (Rat-1) and epithelial breast cancer cells (ZR75) and lentiviral short hairpin RNA-mediated knockdown (KD) clones of KIBRA in ZR75 showed increase in transforming properties with KIBRA overexpression and vice-versa. Results also showed that fibroblasts stably overexpressing KIBRA showed increased tumourigenic potential in nude mice. By adopting a quantitative PCR array-based approach, we identified RASSF1A, a tumour suppressor, as a transcriptional target of KIBRA.Conclusions:This is the first study to demonstrate the in vivo tumourigenic property of KIBRA in a nude mouse model and also unravel the underlying molecular mechanism of KIBRA-mediated transformation via repression of RASSF1A.

Immuno-localization of glucose transporter 4 in healthy human gingiva.

BACKGROUND The gingiva has been shown to be a target tissue for several hormones. Insulin induces uptake of glucose in the peripheral tissues by upregulating the Glucose transporter 4 expression. Little information is available on the expression of Glucose transporter 4 in human gingiva. AIM In this regard, a pilot study was performed with the aim of determining the distribution pattern of Glucose transporter 4 in healthy human gingiva. MATERIALS AND METHODS Immuno-histochemistry was performed on 10 mounted sections of healthy human gingiva with the primary antibody Glucose Transporter 4 (GLUT 4). Appropriate positive and negative controls were used. RESULTS Glucose transporter 4 expression was observed in the basal and suprabasal layers of the gingival epithelium and fibroblasts of the gingival connective tissue. CONCLUSION This may be the first study to demonstrate the expression of GLUT 4 in the healthy human gingiva. The results of this study raise the possibility that gingiva may serve as a target tissue for insulin action.