We note the wide heterogeneity of estimation depending on the GFR estimation equation. In contrast, a recent publication from India Atractylenolide-III detailing the first Benzoylpaeoniflorin estimates from the country’s renal registry revealed almost 50% of presenting cases to be CKD stage 5. This report from India emphasizes the importance of screening programs in resource-poor countries like Cambodia that lack a healthcare system that could bear the significant financial burden of universal access to maintenance renal replacement therapy; in such countries, many of the individuals who present with late-stage CKD are likely to die from the consequences of kidney disease. As chronic diseases continue to play a larger role in early mortality within developing populations, accurate estimates of population burden of chronic diseases will help to determine the true population at risk. Slowing progression to ESRD is a major impetus for CKD detection in populations with limited ability to offer long-term renal replacement therapies such as dialysis and transplantation. Early detection offers the possibility of implementation of treatments that can retard progression. Early-stage detection has the added importance of understanding the mortality-risk of the CKD population, as CKD is associated with an increased likelihood of mortality secondary to cardiovascular disease, as well as being an independent risk factor for early mortality prior to development of ESRD. The limitations of our study include its sample size, that all patients reside in rural areas of Cambodia, and that the CKD-Epi equation used to quantify renal function has not been validated for the Cambodian population. Further, women were over-represented in the cohort, and as we did not have urinalyses for all patients, we were limited in our ability to assess earlier stages of renal insufficiency. The strengths of this study are that it is the first to our knowledge to quantify kidney function estimates for a high-risk population within Cambodia. Studies will need to be performed to assess the burden of disease in urban populations. Future studies will also be needed to explore the association between gender and chronic kidney disease both in rural and urban settings. Inclusion of kidney function in future STEPS analyses would greatly assist in enumerating the burden of disease within the country as 
well as within high-risk groups such as diabetics and patients with hypertension. National or regionlevel renal registries would also direct preventive measures for reducing the incidence and progression of CKD, and help target how and where best to implement renal replacement therapies. Ultimately, a multi-tiered approach of screening, disease treatment, and renal replacement therapy program development will be necessary to address the anticipated increase in the number of Cambodian individuals with CKD. Tumorsphere culture provides important resources for cancer studies, since it enriches and expands tumor cells. However, the efficiency with which long-surviving tumorspheres are established from primary tumors in the nervous system is not satisfactory, whereas tumorspheres are obtained from metastatic tissues with relative ease. For example, only half of primary high-grade gliomas are able to give rise to tumorsphere lines. Low-grade gliomas rarely give rise to tumorspheres. It is also hard to obtain tumorsphere lines from primary neuroblastomas, in contrast to those from metastatic tumors. These low efficiencies of tumorsphere formation from primary tumors seriously limit studies on these cancers. Tumor cells in vivo may reside in a microenvironment suitable for maintenance and growth.