Introduction Translocation of the anaplastic lymphoma kinase (ALK) gene is involved in the tumorigenesis of a subset of non-small cell lung carcinomas (NSCLCs) and identifies patients sensitive to ALK inhibitors. ALK copy number changes and amplification, which plays an oncogenic role in tumors such as neuroblastoma, are poorly characterized in NSCLC. We aimed to study the prevalence of ALK copy number changes and their correlation to ALK protein expression, epidermal growth factor receptor (EGFR) status, and clinicopathological data in patients with NSCLC. Methods ALK status was evaluated by fluorescence in situ hybridization (FISH). Specimens with ALK translocation were studied for echinoderm microtubule-associated protein-like 4 (EML4), KIF5B, and TFG status. ALK expression was assessed by immunohistochemistry. EGFR gene and protein status were evaluated in adenocarcinomas. Survival analysis was performed. Results One hundred seven NSCLC cases were evaluated. There were two cases of EML4-ALK translocation and one with an atypical translocation of ALK. Both cases of EML4-ALK translocation had ALK protein expression, whereas in the rest, ALK was undetected. Eleven cases (10%) exhibited ALK amplification and 68 (63%) copy number gains. There was an association between ALK amplification and EGFR FISH positivity (p < 0.0001) but not with prognosis. In conclusion, EML4-ALK translocation is a rare event in NSCLC. Conclusion The study reveals a significant frequency of ALK amplification and its association with EGFR FISH positivity in lung adenocarcinomas. Based on these findings, a potential role of ALK amplification in the response to ALK inhibitors alone or combined with EGFR inhibitors in NSCLC merits further studies.

Summary Standardized criteria of response to treatment and a unified definition of resistance/intolerance to hydroxycarbamide (HC) in essential thrombocythaemia (ET) have been proposed by the European LeukaemiaNet (ELN). We have retrospectively evaluated such criteria in 166 ET patients treated with HC for a median of 4·5 years. Overall, 134 patients achieved a complete clinicohaematological response (CR) and 25 a partial response. Thirty‐three patients met at least one of the ELN criteria defining resistance (n = 15) or intolerance (n = 21) to HC. Fifteen cases developed anaemia with thrombocytosis, which was associated with a high incidence of myelofibrosis and death from any cause. Other definitions of resistance were less useful. Factors determining the thrombotic risk were a history of prior thrombosis and a baseline leucocyte count >10 × 109/l. Of note, patients achieving a CR, even if sustained during the entire follow‐up, did not benefit from a lower incidence of thrombosis or an improved survival. In conclusion, most ET patients respond to HC, but the achievement of response, as defined by the ELN, does not correlate with the patients’ outcome. The best discriminating ELN criterion of resistance to HC was the detection of anaemia, which also identified a subgroup of patients with poor prognosis.

Therapeutic options for patients with polycythemia vera (PV) and essential thrombocythemia (ET) resistant or intolerant to hydroxyurea are limited. Busulfan is effective as first-line therapy, but there is scarce information on this drug as second-line treatment. The efficacy of busulfan in patients with advanced PV or ET refractory or intolerant to hydroxyurea was assessed in 36 patients (PV n = 15, ET n = 21) treated for a median of 256 days. Complete hematological response (CHR) was achieved in 83 % of patients, after a median time of 203 days (range 92-313). The probability of sustained CHR at 1 and 2 years was 87 and 62 %, respectively. Time to CHR was shorter in patients treated with ≥14 mg of busulfan per week than with lower doses (141 versus 336 days, p = 0.01). Partial molecular response was achieved in three out of nine (33 %) patients. Busulfan was stopped in 27 patients (75 %) due to CHR achievement in 18 cases (67 %), hematological toxicity in 8 cases (30 %), and disease transformation in 1 case. With a median follow-up of 721 days, six patients have died, with the probability of survival at 2 years being 85 %. The probability of thrombosis at 2 years was 11 %. Transformation into acute leukemia or myelodysplastic syndrome was observed in three cases, all of them in a JAK2V617F-negative clone carrying additional mutations. Busulfan, at a dose of 2 mg/day, is an effective option for elderly patients with PV or ET who fail to hydroxyurea, but a significant rate of transformation was observed.

diagnosis of PV required hemoglobin level over 18.5 g/dL in males and over 16.5 g/dL in females, or an increased red cell volume of over 125% of normal values, the demonstration of a mutation in the JAK2 gene, and one minor criteria (decreased erythropoietin serum level, endogenous erythroid colony formation or compatible bone marrow histology). JAK2-negative cases required the presence of at least two minor criteria to establish PV diagnosis. Bone marrow biopsy was performed in all patients with suspicion of ET but it was not routinely assessed in PV. Patients with early/pre-fibrotic primary myelofibrosis were not included in the present study. Informed consent was obtained for the scientific use of the patients' clinico-hematologic data and this was approved by the institutional review board of the Hospital del Mar.Receiving operating characteristic (ROC) curves were performed to evaluate the diagnostic accuracy of Hb and Hct in order to distinguish between normal and increased RCM measured by the Cr51 method. In ROC curves, the specificity and sensitivity of each Hb and Hct value is calculated. The area under the curve (AUC) of a perfect diagnostic test (sensitivity 100%, specificity 100%) is 1 whereas the AUC of a test without diagnostic accuracy is 0.5 (sensitivity 50%, specificity 50%). The best diagnostic test is that with a higher AUC. A diagnostic test is usually considered to have an acceptable diagnostic accuracy when the sensitivity and specificity is higher than 80%, resulting in an AUC of over 0.8. Since the purpose of the present study was to investigate which Hb or Hct value should indicate measurement of RCM (as opposed to not measuring it), the cut off was selected according to sensitivity prevailing over specificity in order to reduce the number of false negative cases. In the differential diagnosis of ET versus PV, false positives represent cases with an Hct or Hb value over a pre-determined threshold but with normal RCM leading to an erroneous diagnosis of PV if RCM is not measured. False negatives (cases with Hct or Hb values below the pre-determined threshold and an increased red cell mass) would correspond to those patients in whom a mistaken diagnosis of ET would be made if RCM was not measured. Results and DiscussionIsotopic RCM was determined as part of the initial evaluation in 179 patients (88 males, 91 females) with a suspected diagnosis of PV or ET. Main hematologic values at diagnosis are shown in Table 1. The majority of patients showed a Hb level and/or platelet counts over the normal values and the JAK2 mutation (V617F or exon 12) was present in 98% of the cases; a clinical picture compatible with PV or ET. RCM was increased in 114 patients establishing a PV diagnosis, whereas ET was diagnosed in 63 of the 65 remaining cases. Two cases with normal RCM did not fulfill ET nor PV criteria at time of evaluation but were diagnosed with PV later on during follow up.The diagnostic accuracy of the WHO Hb criteria is shown in Table 2. WHO Hb criteria showed a high specificity i...