The frequency of human papillomaviruses in colorectal cancer samples in Mashhad, northeastern Iran

Abstract

The estimation of flood hydrographs has a high level of importance in ungauged watersheds.Methods currently being widely used for the estimation of flood hydrographs utilize historical rainfallrunoff data. For ungauged watersheds, the unit hydrograph may be derived using the geomorphologic instantaneous unit hydrograph (GIUH) and geomorphoclimatic instantaneous unit hydrograph (GcIUH) approaches. This research is aimed at comparing the accuracy of GcIUH-based Clark (GcIUH-Clark) and GIUH-based Nash (GIUH-Nash) models. For this purpose, the Clark-IUH model option of the HEC-HMS package and the Nash-IUH model were employed with and without the use of historical rainfall-runoff data, respectively, to determine shape, peak discharge, and time to peak of direct surface run-off (DSRO) hydrographs. The case study in this study was the Kasilian watershed, located in Mazandaran Province of Iran, with an area of 67.5 km 2 . The results obtained from these models were compared with observed DSRO hydrographs based on 3 performance criteria, namely EFF, PEP, and PETP.The results clearly revealed the accuracy and applicability of these 2 models (the GcIUH-Clark model and the GIUH-Nash model) for derivation of DSRO hydrographs.

Does human papillomavirus cause human colorectal cancer? Applying Bradford Hill criteria postulates

“…In Iran, so far, n = 8 studies [ 17 , 30 , 37 , 39 , 43 , 75 , 79 , 80 ] have been reported to elaborate the HPV aetiology in CRC. From them, only n = 3 studies [ 30 , 39 , 43 ] were the case–control studies.…”

“…How we can be sure that negative results for HPV detection in the investigating samples are not due to the poor quality of the extracted DNA? Many studies utilised positive control to avoid such situations [ 17 , 30 , 39 , 43 , 80 ], but few studies [ 18 , 24 , 34 , 65 ] did not use positive control, so there is no way to confirm their negative results. The choice of inappropriate primers could lead to false-negative results, for example, primers that target L1 region of the HPV genome may be unreliable for the detection of HPV in tissues of advanced carcinomas, as L1 and E1 regions may be lost during the integration of viral genome into the host genome, whereas the E6/E7 regions remained consistently present, so this is the plausible explanation for the completely negative results of the studies [ 17 , 26 , 41 , 43 , 46 ].…”

“…The case–control studies are necessary to establish a causal relationship between the causative agent and the disease. Some of the studies that we summarised analysed only the CRC samples [ 8 , 11 , 13 , 59 , 64 , 65 , 67 , 71 , 74 , 75 , 79 , 80 , 84 ] and did not allow us to compare their results with normal or adjacent/benign controls. However, most of the studies also analysed the normal and adjacent/benign tissues along with CRC samples, and the comparison of their results demonstrated that HPV detection positivity ratios in CRC samples were higher in [ 12 , 17 , 27 , 29 – 32 , 35 – 57 ] studies, whereas lower in [ 28 , 33 , 34 , 58 ] studies as compared to the normal and adjacent/benign controls.…”

Detection of Human papillomavirus and the role of p16INK4a in colorectal carcinomas

“…Genotyping was performed by reverse hybridization using the INNO-LiPA HPV Genotyping Extra II Kit (Fujirebio Europe 1 ). The assay allows the identification of 32 HPV genotypes, currently known as high risk genotypes [16,18,31,33,35,39,45,51,52,56,58,59,68], probable high risk [26,53,66,70,73,82] and low risk [6,11,40,42,43,44,54,61,62,67,81,83,89].…”

“…found [9,40,53,[57][58][59][60][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82]. In the studies evaluated, the prevalence of HPV in CRCs ranged from 0 to 57.1%.…”