Rearranged EML4-ALK fusion transcripts sequester in circulating blood platelets and enable blood-based crizotinib response monitoring in non-small-cell lung cancer.

PURPOSE: Non-small-cell lung cancers harboring EML4-ALK rearrangements are sensitive to crizotinib. However, despite initial response, most patients will eventually relapse, and monitoring EML4-ALK rearrangements over the course of treatment may help identify these patients. However, challenges associated with serial tumor biopsies have highlighted the need for blood-based assays for the monitoring of biomarkers. Platelets can sequester RNA released by tumor cells and are thus an attractive source for the non-invasive assessment of biomarkers. METHODS: EML4-ALK rearrangements were analyzed by RT-PCR in platelets and plasma isolated from blood obtained from 77 patients with non-small-cell lung cancer, 38 of whom had EML4-ALK-rearranged tumors. In a subset of 29 patients with EML4-ALK-rearranged tumors who were treated with crizotinib, EML4-ALK rearrangements in platelets were correlated with progression-free and overall survival. RESULTS: RT-PCR demonstrated 65% sensitivity and 100% specificity for the detection of EML4-ALK rearrangements in platelets. In the subset of 29 patients treated with crizotinib, progression-free survival was 3.7 months for patients with EML4-ALK+ platelets and 16 months for those with EML4-ALK- platelets (hazard ratio, 3.5; P = 0.02). Monitoring of EML4-ALK rearrangements in the platelets of one patient over a period of 30 months revealed crizotinib resistance two months prior to radiographic disease progression. CONCLUSIONS: Platelets are a valuable source for the non-invasive detection of EML4-ALK rearrangements and may prove useful for predicting and monitoring outcome to crizotinib, thereby improving clinical decisions based on radiographic imaging alone.

Serum GFAP levels in optic neuropathies.

BACKGROUND: Complement mediated autoimmunity against aquaporin-4 results in astrocytic damage in neuromyelitis optica (NMO). There is evidence for increased CSF glial fibrillary acidic protein (GFAP) and S100B levels in acute NMO. Here we tested whether the CSF finding also holds true for the diagnostic value of serum GFAP and S100B levels in NMO. METHODS: A multicentre study included 322 patients from London (n=160), Nijmegen (n=95), Pecs (n=44), and Lyon (n=24). Patients were classified into the following diagnostic categories: neurological control patients (n=45), MS optic neuritis (MSON, n=38), isolated optic neuritis (ION, n=11), relapsing isolated optic neuritis (RION, n=48), chronic relapsing isolated optic neuropathy (CRION, n=18), unclassified optic neuritis (UCON, n=39), NMO (n=77) and relapsing remitting multiple sclerosis (RRMS, n=47). Serum GFAP and S100B levels were quantified using ELISA. RESULTS: Median serum GFAP but not S100B levels were significantly higher (p<0.0001, general linear model) in patients with NMO (4.83 pg/mL) if compared to MSON (1.5 pg/mL, p=0.0001), UCON (1.92 pg/mL, p<0.01), ION (0.0 ng/mL, p<0.05), RION (1.3 pg/mL, p<0.0001) and CRION (2.2 pg/mL, p=0.01). Serum GFAP levels in the control cohort (3.6 pg/mL) were not significantly different to NMO. There was no relationship between serum GFAP levels and any other clinical or demographic parameter. Serum S100B concentrations correlated with the number of relapses in MSON (R=0.83, p=0.005). CONCLUSION: In contrast to the CSF, neither serum GFAP nor S100B levels were of major diagnostic value for the laboratory supported differential diagnosis between optic neuritis in the context of NMO and other optic neuropathies.