Satyajit Pradhan

Segmentation and classification of medical images using texture-primitive features: Application of BAM-type artificial neural network

The objective of developing this software is to achieve auto-segmentation and tissue characterization. Therefore, the present algorithm has been designed and developed for analysis of medical images based on hybridization of syntactic and statistical approaches, using artificial neural network (ANN). This algorithm performs segmentation and classification as is done in human vision system, which recognizes objects; perceives depth; identifies different textures, curved surfaces, or a surface inclination by texture information and brightness. The analysis of medical image is directly based on four steps: 1) image filtering, 2) segmentation, 3) feature extraction, and 4) analysis of extracted features by pattern recognition system or classifier. In this paper, an attempt has been made to present an approach for soft tissue characterization utilizing texture-primitive features with ANN as segmentation and classifier tool. The present approach directly combines second, third, and fourth steps into one algorithm. This is a semisupervised approach in which supervision is involved only at the level of defining texture-primitive cell; afterwards, algorithm itself scans the whole image and performs the segmentation and classification in unsupervised mode. The algorithm was first tested on Markov textures, and the success rate achieved in classification was 100%; further, the algorithm was able to give results on the test images impregnated with distorted Markov texture cell. In addition to this, the output also indicated the level of distortion in distorted Markov texture cell as compared to standard Markov texture cell. Finally, algorithm was applied to selected medical images for segmentation and classification. Results were in agreement with those with manual segmentation and were clinically correlated.

Over Expression of Minichromosome Maintenance Genes is Clinically Correlated to Cervical Carcinogenesis

Minichromosome Maintenance (MCM) proteins play important roles in cell cycle progression by mediating DNA replication initiation and elongation. Among 10 MCM homologues MCM 2–7 form a hexamer and assemble to the pre-replication complex acting as replication licensing factors. Binding and function of MCM2-7 to pre-replication complex is regulated by MCM10 mediated binding of RECQL4 with MCM2-7. The purpose of this study is to explore the role of MCMs in cervical cancer and their correlation with the clinical parameters of cervical cancer. We have investigated sixty primary cervical cancer tissue samples, eight cervical cancer cell lines and thirty hysterectomised normal cervical tissue. The expression profiling of MCMs was done using semi-quantitative RT-PCR, immunoblotting and immunohistochemistry. MCM2, 4, 5, 6, 7, 10 and RECQL4 are significantly over-expressed in cervical cancer. Among these, MCM4, 6 and 10 show increased frequency of over expression along with advancement of tumor stages. MCM4, 5 and 6 also show differential expression in different types of lesion, while MCM2 and MCM10 are over expressed in cervical cancer irrespective of clinico-pathological parameters. Our data indicates the role of MCM4, MCM5, MCM6, MCM10 and RECQL4 in the progression of cervical cancer.

PI3K/AKT pathway-mediated regulation of p27 Kip1 is associated with cell cycle arrest and apoptosis in cervical cancer

BackgroundThe cyclin-dependent kinase inhibitor p27Kip1 is known to act as a putative tumor suppressor in several human cancers, including cervical cancer. Down-regulation of p27Kip1 may occur either through transcription inhibition or through phosphorylation-dependent proteolytic degradation. As yet, the mechanism underlying p27Kip1 down-regulation and its putative downstream effects on cervical cancer development are poorly understood. Here we assessed the expression and sub-cellular localization of p27Kip1 and its effects on proliferation, cell cycle progression and (inhibition of) apoptosis in cervical cancer cells.MethodsPrimary cervical cancer samples (n = 70), normal cervical tissue samples (n = 30) and cervical cancer-derived cell lines (n = 8) were used to assess the expression of p27Kip1 and AKT1 by RT-PCR, Western blotting and immunohistochemistry, respectively. The effects of the PI3K inhibitor LY294004 and the proteasome inhibitor MG132 on cervical cancer cell proliferation were investigated using a MTT assay. Apoptosis and cell cycle analyses were carried out using flow cytometry, and sub-cellular p27Kip1 localization analyses were carried out using immunofluorescence assays.ResultsWe observed p27Kip1 down-regulation (p = 0.045) and AKT1 up-regulation (p = 0.046) in both the primary cervical cancer samples and the cervical cancer-derived cell lines, compared to the normal cervical tissue samples tested. Treatment of cervical cancer-derived cell lines with the PI3K inhibitor LY294002 resulted in a reduced AKT1 activity. We also observed a dose-dependent inhibition of cell viability after treatment of these cell lines with the proteasome inhibitor MG132. Treatment of the cells with LY294002 resulted in a G1 cell cycle arrest, a nuclear expression of p27Kip1, and a cytoplasmic p27Kip1 accumulation after subsequent treatment with MG132. Additionally, we found that the synergistic effect of MG132 and LY294002 resulted in a sub-G1 cell cycle arrest and apoptosis induction through poly (ADP-ribose) polymerase (PARP) cleavage.ConclusionOur data suggest that p27Kip1 down-regulation in cervical cancer cells is primarily regulated through PI3K/AKT-mediated proteasomal degradation. The observed synergistic effect of the MG132 and LY294002 inhibitors may form a basis for the design of novel cervical cancer therapies.

MCM Paradox: Abundance of Eukaryotic Replicative Helicases and Genomic Integrity

As a crucial component of DNA replication licensing system, minichromosome maintenance (MCM) 2–7 complex acts as the eukaryotic DNA replicative helicase. The six related MCM proteins form a heterohexamer and bind with ORC, CDC6, and Cdt1 to form the prereplication complex. Although the MCMs are well known as replicative helicases, their overabundance and distribution patterns on chromatin present a paradox called the “MCM paradox.” Several approaches had been taken to solve the MCM paradox and describe the purpose of excess MCMs distributed beyond the replication origins. Alternative functions of these MCMs rather than a helicase had also been proposed. This review focuses on several models and concepts generated to solve the MCM paradox coinciding with their helicase function and provides insight into the concept that excess MCMs are meant for licensing dormant origins as a backup during replication stress. Finally, we extend our view towards the effect of alteration of MCM level. Though an excess MCM constituent is needed for normal cells to withstand stress, there must be a delineation of the threshold level in normal and malignant cells. This review also outlooks the future prospects to better understand the MCM biology.

Doppler ultrasound scoring to predict chemotherapeutic response in advanced breast cancer

BackgroundDoppler ultrasonography (US) is increasingly being utilized as an imaging modality in breast cancer. It is used to study the vascular characteristics of the tumor. Neoadjuvant chemotherapy is the standard modality of treatment in locally advanced breast cancer. Histological examination remains the gold standard to assess the chemotherapy response. However, based on the color Doppler findings, a new scoring system that could predict histological response following chemotherapy is proposed.MethodsFifty cases of locally advanced infiltrating duct carcinoma of the breast were studied. The mean age of the patients was 44.5 years. All patients underwent clinical, Doppler and histopathological assessment followed by three cycles of CAF (Cyclophosphamide, Adriamycin and 5-Fluorouracil) chemotherapy, repeat clinical and Doppler examination and surgery. The resected specimens were examined histopathologically and histological response was correlated with Doppler findings. The Doppler characteristics of the tumor were graded as 1–4 for <25%, 25–50%, >50% and complete disappearance of flow signals respectively. A cumulative score was calculated and compared with histopathological response. Results were analyzed using Chi square test, sensitivity, specificity, positive and negative predictive values.ResultsThe maximum Doppler score according to the proposed scoring system was twelve and minimum three. Higher scores corresponded with a more favorable histopathological response. Twenty four patients had complete response to chemotherapy. Sixteen of these 24 patients (66.7%) had a cumulative Doppler score more than nine. The sensitivity of cumulative score >5 was 91.7% and specificity was 38.5%. The area under the ROC curve of the cumulative score >9 was 0.72.ConclusionDoppler scoring can be accurately used to objectively predict the response to chemotherapy in patients with locally advanced breast cancer and it correlates well with histopathological response.

Segmentation of medical images using Simulated Annealing Based Fuzzy C Means algorithm

Accurate segmentation is desirable for analysis and diagnosis of medical images. This study provides methodology for fully automated simulated annealing based fuzzy c-means algorithm, modelled as graph search method. The approach is unsupervised based on pixel clustering using textural features. The virtually training free algorithm needs initial temperature and cooling rate as input parameters. Experimentation on more than 180 MR and CT images for different parameter values, has suggested the best-suited values for accurate segmentation. An overall 97% correct segmentation has been achieved. The results, evaluated by radiologists, are of clinical importance for segmentation and classification of Region of Interest.

Effect of Prevailing Local Treatment Options of Breast Cancer on Survival Outside Controlled Clinical Trials: Experience of a Specialist Breast Unit in North India

BackgroundThis study aimed at analyzing different treatments of breast cancer (BC) prevalent in the region, their effect on patients’ survival, and discusses the most suitable method within available resources.MethodsThe study was set up at a tertiary care hospital in north India. We retrospectively reviewed data of 473 female BC patients who attended the departments of Surgical Oncology and Radiotherapy from January 1997 to December 1999. Patients with cTNM stage IV and inoperable stage III were included; those who defaulted or were lost to follow-up were excluded. Out of 473 patients, 372 were selected. The selected patients were divided into groups on the basis of place and type of local treatment they received: (1) local excision only, (2) standard breast conservation therapy (BCT), (3) total mastectomy (TM) + axillary lymph node dissection + radiotherapy (RT), and (4) modified radical mastectomy (MRM) + RT. Data regarding recurrence and survival were analyzed in December 2005. Minimum follow-up was 6 years.ResultsOverall recurrence rates were significantly higher in patients operated elsewhere (P <0.0001). Of 194 operated at our Breast Unit, 25 (14.6%) of 171 MRM patients and none of 23 BCT had recurrence. Of 178 patients operated elsewhere, 44 (100%), 6 (42.9%), 41 (41%), and 8 (40%) developed recurrence in groups 1, 2, 3, and 4 respectively. Overall survival was significantly better in patients with MRM at our unit versus TM outside (93.6% vs. 80%).ConclusionsSeveral types of treatment from improper local excision alone, BCT, TM, to a carefully done MRM are prevalent here. Properly done, MRM yields significant local control with survival benefit and appears to remain the gold standard in management of our BC patients.

Epigenetic Silencing of CXCR4 Promotes Loss of Cell Adhesion in Cervical Cancer

In the network of chemokine signaling pathways, recent reports have described the SDF-1α/CXCR4 axis and its role in cancer progression and metastasis. Interestingly, we found downregulation of CXCR4 at both transcript and protein level in cervical cancer cell lines and primary tumors. We also found CXCR4 promoter hypermethylation in cervical cancer cell lines and primary biopsy samples. DNA hypomethylating drug 5-AZA-2′-deoxycytidine and histone deacetylase inhibitor Trichostatin A treatments in cell lines reactivate both CXCR4 transcription and protein expression. Cell adhesion assay demonstrated that autocrine SDF-1α promotes the loss of cell adhesion while paracrine SDF-1α predominantly protects the normal cervical cells from loss of cell adhesion. Cervical cancer cell line C-33A having increased expression of CXCR4 after TSA treatment showed increased cell adhesion by paracrine source of SDF-1α in comparison to untreated C-33A. These findings demonstrate the first evidence that epigenetic silencing of CXCR4 makes the cells inefficient to respond to the paracrine source of SDF-1α leading to loss of cell adhesion, one of the key events in metastases and progression of the disease. Our results provide novel insight of SDF-1α/CXCR4 signaling in tumor microenvironment which may be promising to further delineate molecular mechanism of cervical carcinogenesis.

Carcinoma of the gallbladder presenting as scalp tumour

Carcinoma of the gallbladder is characterized by rapid tumour growth associated with lymphatic and local tumour invasion. The peritoneum, GIT and lungs are common sites of seeding. Distant metastasis to bone rarely occurs. Here we document a case of silent gallbladder carcinoma presenting as scalp tumour with improved survival.

Assessment of Predictive Markers of Response to Neoadjuvant Chemotherapy in Breast Cancer

OBJECTIVE To identify the predictive markers associated with chemotherapy sensitivity, especially those producing pathological complete response (pCR) following neoadjuvant chemotherapy (NACT) in patients with locally advanced breast cancer. METHODS Core needle biopsy of 50 locally advanced breast cancer patients was analysed for histopathology, grade, oestrogen receptor, progesterone receptor, HER2, Ki-67, p53, Bcl-2, and BAX before starting NACT. This was correlated with response to NACT using Response Evaluation Criteria in Solid Tumours criteria. RESULTS The mean tumour reduction rate per chemotherapy cycle was significantly higher in BAX-positive (p = 0.01) and Bcl-2-negative (p = 0.04) tumours. BAX expression significantly (p = 0.043) correlated with a response of an at least 30% reduction in tumour size post-NACT on multivariate analysis. A significant relationship was seen between loss of Bcl-2 expression and pCR on univariate (p = 0.048) analysis. Overall, all of the above 12 parameters had 30.4% and 28.5% success in predicting clinical complete response and pCR, respectively, by the Cox and Snell formula. CONCLUSION Of all parameters examined, only the apoptosis-related genes (Bcl-2 and BAX) seemed to exert some influence on the response to NACT, and neither by itself was sufficient to predict pCR; however, 50 patients is not sufficient to simultaneously analyse several predictive markers.