Hemalata Hospitals and Research Centre

Aims: Radiotherapy is predominantly used as one of the treatment modalities to treat local tumor in colorectal cancer (CRC). Hindrance in disease treatment can be attributed to radio-tolerance of cancer stem cells (CSCs) subsistence in the tumor. Understanding the radio-resistant property of CSCs might help in the accomplishment of targeted radiotherapy treatment and increased disease-free survival. Telomeric RAP1 contributes in modulation of various transcription factors leading to aberrant cell proliferation and tumor cell migration. Therefore, we investigated the role of RAP1 in maintaining resistance phenotype and acquired stemness in radio-resistant cells.Main methods: Characterization of HCT116 derived radio-resistant cell (HCT116RR) was performed by cell survival and DNA damage profiling. RAP1 silenced cells were investigated for DNA damage and expression of CSC markers through western blotting and Real-time PCR post-irradiation. Molecular docking and co-immunoprecipitation study were performed to investigate RAP1 and KLF4 interaction followed by RAP1 protein status profiling in CRC patient.Key findings: We established radio-resistant cells, which showed tolerance to radiotherapy and elevated expression of CSC markers along with RAP1. RAP1 silencing showed enhanced DNA damage and reduced expression of CSC markers post-irradiation. We observed strong physical interaction between RAP1 and KLF4 protein. Furthermore, higher RAP1 expression was observed in the tumor of CRC patients. Dataset analysis also revealed that high expression of RAP1 expression is associated with poor prognosis.Significance: We conclude that higher expression of RAP1 implicates its possible role in promoting radio-resistance in CRC cells by modulating DNA damage and CSC phenotype.

Objectives: Touch imprint cytology (TIC) of biopsy specimen can be utilized for a rapid on-site evaluation of tumors. Its usefulness for intraoperative diagnosis is well known. We evaluated the advantages and limitations of TIC of trucut biopsies of intraabdominal tumors. Materials and Methods: TIC was obtained in 42 consecutive cases of intraabdominal masses. The sensitivity, specificity, and diagnostic accuracy of TIC were evaluated by comparing it with the final biopsy diagnosis. Results: The study included retroperitoneal tumors (13 cases, 30.95%), liver mass (11 cases, 26.19%), gall bladder mass (4 cases, 9.53%), pelvic mass (3 cases, 7.14%), iliac bone mass (2 cases, 4.76%), mesenteric nodule (4 cases, 9.53%), kidney mass (3 cases, 7.14%), and 1 case (2.38%) each of epigastric mass and loin mass. Thirty-two (76.19%) cases were diagnosed as malignant and 10 (23.81%) cases were diagnosed as benign/negative on TIC. The overall sensitivity was 87.88%, the specificity was 77.78%, the positive predictive value was 93.55%, and the negative predictive value was 63.60%. The accuracy of the test was 85.71%.Conclusions: TIC is a simple and cost-effective method that aids in the diagnostic evaluation of tumors. It is fairly accurate with high positive predictive value and hence can be used as an adjunct to the biopsy diagnosis.

Touch imprint cytology (TIC) is a very rapid, cheap, and easy method used for the rapid evaluation of intraoperative specimens and post mortem cases. This study aims to evaluate its utility in preoperative diagnosis of cancer. A total of 476 cases of suspected malignancy of different sites and different histological subtypes were studied. TIC was obtained in all the biopsies and the cytological findings were correlated with the corresponding biopsy diagnosis to evaluate the diagnostic accuracy. TIC was satisfactory for evaluation with respect to the cellularity and cell morphology in 468 (98.3%) cases. Overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 96.9, 97.4, 99.1, 91.2, and 97.1%, respectively. The accuracy varied with the site of biopsy. The accuracy for soft tissue lesions was 92% whereas it was 100% for sites like thyroid, anal canal, rectum, and prostate. TIC is a simple and rapid technique and gives fairly accurate diagnosis while the cost is much less than the traditional histopathological techniques. The presence or absence of malignancy and the exact subtype can be diagnosed reliably making it quiet useful for preoperative cancer diagnosis. Diagn. Cytopathol. 2017;45:507-512. © 2017 Wiley Periodicals, Inc.