The overall rate variant detection was 50.6% (44/87) in this study, which is comparable to the worldwide variations detection rate of 65% if the difference between the frequency of variants in CEP290 is taken into consideration (CEP290 mutations occur in 15% of Caucasian patients but in only in 6.4% of Chinese patients) [2].
There were no significant variation in detection rate of AFB1-albumin adducts among study townships (ranging from 33.3 to 47.5%), seasonality of sample collection (ranging from 36.8 to 43.0%) and age groups (ranging from 26.9 to 40.6%).
Variations in detection rate may be expected, as the populations being tested will be different for different laboratories and health settings.
We have recently presented national data showing nearly a hundred fold variation in detection rates of OASI [ 51].
The wide variation in detection rates is not surprising, given the different screening criteria for IEM used in different countries, and the inconsistent sample-collection methods.
Variation in detection rates among equine population in these study areas could be due to the differences in the rate of exposure to infection, samples analysed, immune status of the horses, season, and breed of the horses.
Although some temporal variation in detection rates is recognised (Peto et al, 1999), the different sources of 'genuine' mesotheliomas used (mesothelioma registry vs cancer registry) may also be important.
This variation in detection rates could have been due to the unforeseen nonspecificity of the real-time PCR, or to the inherent lower sensitivity of conventional PCRs, because most real-time PCR positive samples produced late signals at cycle threshold values ≈40.
This variability reflects inconsistent diagnostic criteria, inappropriate histological classification of different subtypes, variation in polyp detection rate among endoscopists, application of enhancing endoscopic modalities, and population selection criteria.
However, as acknowledged by the authors, pathology misclassification, variation in polyp detection rate among endoscopists and use of standard white-light endoscopy represent limitations, which may have underestimated the prevalence of SPs.
