Assessment of the interlaboratory variability and robustness of JAK2V617F mutation assays: A study involving a consortium of 19 Italian laboratories.

To date, a plenty of techniques for the detection of JAK2V617F is used over different laboratories, with substantial differences in specificity and sensitivity. Therefore, to provide reliable and comparable results, the standardization of molecular techniques is mandatory.A network of 19 centers was established to 1) evaluate the inter- and intra-laboratory variability in JAK2V617F quantification, 2) identify the most robust assay for the standardization of the molecular test and 3) allow consistent interpretation of individual patient analysis results. The study was conceived in 3 different rounds, in which all centers had to blindly test DNA samples with different JAK2V617F allele burden (AB) using both quantitative and qualitative assays.The positivity of samples with an AB < 1% was not detected by qualitative assays. Conversely, laboratories performing the quantitative approach were able to determine the expected JAK2V617F AB. Quantitative results were reliable across all mutation loads with moderate variability at low AB (0.1 and 1%; CV = 0.46 and 0.77, respectively). Remarkably, all laboratories clearly distinguished between the 0.1 and 1% mutated samples.In conclusion, a qualitative approach is not sensitive enough to detect the JAK2V617F mutation, especially at low AB. On the contrary, the ipsogen JAK2 MutaQuant CE-IVD kit resulted in a high, efficient and sensitive quantification detection of all mutation loads. This study sets the basis for the standardization of molecular techniques for JAK2V617F determination, which will require the employment of approved operating procedures and the use of certificated standards, such as the recent WHO 1st International Reference Panel for Genomic JAK2V617F.

Toxic encephalopathy in elderly patients during treatment with capecitabine: literature review and a case report.

Capecitabine is now-a-days rapidly replacing 5-Fluorouracil in daily clinical practice. Neurologic toxicity during a treatment with fluoropyrimidines, as 5-fluorouracil, represents a well-known side-effect, largely described in literature. Central nervous system (CNS) toxicity, mainly encephalopathy with or without seizures, occurs occasionally even when conventional doses are used. CNS toxicity incidence increases markedly when the blood-brain barrier is either overwhelmed or bypassed (Hildebrand J. Neurological complications of cancer chemotherapy. Curr Opin Oncol 2006; 18: 321-324). Peripheral nervous system (PNS) toxicity is more common because proximal and distal extremities of the peripheral nerves are not protected by a blood-brain like barrier and peripheral neuropathy remains a major limiting factor for the administration of conventional doses of several agents (Saif W, Wood TE, McGee PJ and Diasio RB. Peripheral neuropathy associated with capecitabine, Anticancer Drugs 2004;15: 767-771). Capecitabine is a prodrug of 5-fluorouracil, more easily administered by mouth; its transformation in 5-fluorouracil is performed in the liver. There are only a few reports on the toxic neurological side-effects of capecitabine. We describe in our report a rare case of toxic encephalopathy in a 82-year-old female, with a brief review of literature. In the literature reviewed, we found 12 neurologic episodes due to capecitabine lasting between a few days till some months. All clinical symptoms of the cases described in literature, obtained a complete regression with the discontinuation of capecitabine. A relation was not found with dihydropyrimidine dehydrogenase (DPD) mutation, also if pharmacologic and pharmacogenetic assessment should be done for this drug, especially in old patients. Toxic encephalopathy represents a rare event during capecitabine treatment and on the bases of the data found, is fairly managed in the clinical setting. The knowledge of the natural history of the toxic effect allows the use of the drug also in old patients.