Early pneumothorax as a feature of response to crizotinib therapy in a patient with ALK rearranged lung adenocarcinoma.

BACKGROUND: Single arm phase 1 and 2 studies on Crizotinib in ALK-positive patients so far have shown rapid and durable responses. Spontaneous pneumothoraces as a result of response to anti-cancer therapy are rare in oncology but have been documented in a number of tumour types including lung cancer. This includes cytotoxic chemotherapy as well as molecular targeted agents such as gefitinib and Bevacizumab. These often require chest drain insertion or surgical intervention with associated morbidity and mortality. They have also been associated with response to treatment. This is the first report we are aware of documenting pneumothorax as response to crizotinib therapy. CASE PRESENTATION: A 48-year-old Caucasian male presented with a Stage IV, TTF1 positive, EGFR wild-type adenocarcinoma of the lung. He received first line chemotherapy with three cycles of cisplatin-pemetrexed chemotherapy with a differential response, and then second-line erlotinib for two months before further radiological evidence of disease progression. Further analysis of his diagnostic specimen identified an ALK rearrangement by fluorescence in situ hybridization (FISH). He was commenced on crizotinib therapy 250 mg orally twice daily. At his 4-week assessment he had a chest radiograph that identified a large left-sided pneumothorax with disease response evident on the right. Chest CT confirmed a 50% left-sided pneumothorax on a background of overall disease response. A chest tube was inserted with complete resolution of the pneumothorax that did not recur following its removal. CONCLUSION: Our case demonstrates this potential complication of crizotinib therapy and we therefore recommend that pneumothorax be considered in patients on crizotinib presenting with high lung metastatic burden and with worsening dyspnoea.

Tyrosine kinase inhibitor insensitivity of non-cycling CD34+ human acute myeloid leukaemia cells with FMS-like tyrosine kinase 3 mutations.

The efficacy of tyrosine kinase (TK) inhibitors on non-cycling acute myeloid leukaemia (AML) cells, previously shown to have potent tumourigenic potential, is unknown. This pilot study describes the first attempt to characterize non-cycling cells from a small series of human FMS-like tyrosine kinase 3 (FLT3) mutation positive samples. CD34+ AML cells from patients with FLT3 mutation positive AML were cultured on murine stroma. In expansion cultures, non-cycling cells were found to retain CD34+ expression in contrast to dividing cells. Leukaemic gene rearrangements could be detected in non-cycling cells, indicating their leukaemic origin. Significantly, the FLT3-internal tandem duplication (ITD) mutation was found in the non-cycling fraction of four out of five cases. Exposure to the FLT3-directed inhibitor TKI258 clearly inhibited the growth of AML CD34+ cells in short-term cultures and colony-forming unit assays. Crucially, non-cycling cells were not eradicated, with the exception of one case, which exhibited exquisite sensitivity to the compound. Moreover, in longer-term cultures, TKI258-treated non-cycling cells showed no growth impairment compared to treatment-naive non-cycling cells. These findings suggest that non-cycling cells in AML may constitute a disease reservoir that is resistant to TK inhibition. Further studies with a larger sample size and other inhibitors are warranted.

Wt1 is not essential for hematopoiesis in the mouse.

WT1 has been implicated in human leukemia and hematopoiesis, but its role in stem cell differentiation is not yet fully defined. We show that Wt1-null murine fetal liver cells are capable of reconstituting functional hematopoiesis following transplantation into irradiated recipients. There was also no significant difference between the in vitro colony-forming ability of wild-type and Wt1-null cells. Using a reporter gene assay in a transgenic mouse system, expression from the WT1 promoter was detectable in adult bone marrow, but undetectable in subsets of different hematopoietic cells. We conclude that Wt1 is not essential for murine hematopoiesis and that there may be significant differences in its role between mouse and man.

Fluorescence In Situ Hybridization for MDM2 Amplification as a Routine Ancillary Diagnostic Tool for Suspected Well-Differentiated and Dedifferentiated Liposarcomas: Experience at a Tertiary Center.

Background. The assessment of MDM2 gene amplification by fluorescence in situ hybridization (FISH) has become a routine ancillary tool for diagnosing atypical lipomatous tumor (ALT)/well-differentiated liposarcoma and dedifferentiated liposarcoma (WDL/DDL) in specialist sarcoma units. We describe our experience of its utility at our tertiary institute. Methods. All routine histology samples in which MDM2 amplification was assessed with FISH over a 2-year period were included, and FISH results were correlated with clinical and histologic findings. Results. 365 samples from 347 patients had FISH for MDM2 gene amplification. 170 were positive (i.e., showed MDM2 gene amplification), 192 were negative, and 3 were technically unsatisfactory. There were 122 histologically benign cases showing a histology:FISH concordance rate of 92.6%, 142 WDL/DDL (concordance 96.5%), and 34 cases histologically equivocal for WDL (concordance 50%). Of 64 spindle cell/pleomorphic neoplasms (in which DDL was a differential diagnosis), 21.9% showed MDM2 amplification. Of the cases with discrepant histology and FISH, all but 3 had diagnoses amended following FISH results. For discrepancies of benign histology but positive FISH, lesions were on average larger, more frequently in "classical" (intra-abdominal or inguinal) sites for WDL/DDL and more frequently core biopsies. Discrepancies of malignant histology but negative FISH were smaller, less frequently in "classical" sites but again more frequently core biopsies. Conclusions. FISH has a high correlation rate with histology for cases with firm histologic diagnoses of lipoma or WDL/DDL. It is a useful ancillary diagnostic tool in histologically equivocal cases, particularly in WDL lacking significant histologic atypia or DDL without corresponding WDL component, especially in larger tumors, those from intra-abdominal or inguinal sites or core biopsies. There is a significant group of well-differentiated adipocytic neoplasms which are difficult to diagnose on morphology alone, in which FISH for MDM2 amplification is diagnostically contributory.

Incidence of MLL rearrangement in acute myeloid leukemia, and a CALM-AF10 fusion in M4 type acute myeloblastic leukemia.

To determine the incidence of the mixed lineage leukemia (MLL) gene rearrangements in acute myeloid leukemia (AML) without cytogenetically-detected 11q23 abnormalities, we screened 64 cases of AML at diagnosis for MLL rearrangement by FISH. Three cases (4.7%) had a MLL rearrangement detected; one was shown to have a cryptic t(11;22)(q23;q11) and another to have a t(9;11)(p21-22;q23) which had been missed by the conventional cytogenetic study. No 11q23 structural abnormality was visible in the third case. Twenty-six of the 64 cases were further studied by Southern blotting and DNA hybridization, and four of these cases (15%) were found to have MLL rearrangement: in three of these, FISH had not detected any abnormality. FISH was also used to confirm MLL involvement in eight cases of AML that had a cytogenetic abnormality at 11q23; in one of these, Southern blot did not show a rearrangement. The survival of patients with MLL abnormalities identified by cytogenetics, FISH and/or DNA analysis was significantly worse than that of patients without MLL abnormalities (event-free survival p = 0.016) although two patients with a t(9;11)(p21-22;q23) were long-term survivors, consistent with this particular translocation having a better prognosis. One further case with a cytogenetic abnormality close to 11q23 was studied; it was found to have a t(10;11)(p13;q21), and the breakpoints were shown by FISH to involve the Clathrin Assembly Lymphoid Myeloid (CALM) gene at 11q21 and the AF10 gene at 10p13. Our data confirm the value of combining cytogenetic, FISH and molecular analyses to define the incidence and precise nature of MLL and 11q23 abnormalities in AML.

Isolated bone marrow involvement in diffuse large B cell lymphoma: a report of three cases with review of morphological, immunophenotypic and cytogenetic findings.

Diffuse large B cell lymphoma (DLBL) comprises a heterogenous entity characterized by the presence of large cells, exhibiting a mature B cell phenotype. The high proliferation rate and aggressive disease remain a therapeutic challenge, but the apparent biological diversity permits a risk-stratification model for prognostic grouping through the International Prognostic Index (IPI). Empirical to this approach is the consideration of cytogenetic data, offering an insight into the pathogenetic events which may underlie neoplastic clonal evolution and disease progression. We describe three cases of DLBL presenting with isolated marrow disease, a rare primary finding in this lymphoma. All three cases showed involvement of blood and bone marrow without evidence of splenic or lymph node involvement on imaging studies. Histological and immunophenotypic findings were similar in all three cases, outlining the phenotypic maturity of this disease. Cytogenetic analysis revealed complex karyotypes in the two cases examined. M-FISH (multicolour fluorescent in situ hybridization) performed on bone marrow from case 1 showed several cryptic translocations not evident on G-banding, including a novel translocation between 2p and 9p, and an unbalanced translocation between 14q and 11q. Cytogenetic analysis in case 2 showed abnormalities involving 7q, 9p at the site of the INK4a gene, and the bcl-2 locus, findings confirmed by M-FISH. These cases serve to highlight the biological and cytogenetic heterogenity of DLBL and emphasize the need for complementary investigations in the characterization of this entity.

ALK translocation is associated with ALK immunoreactivity and extensive signet-ring morphology in primary lung adenocarcinoma.

BACKGROUND: ALK rearrangement is particularly observed in signet-ring sub-type adenocarcinoma. Since fluorescence in situ hybridization (FISH) is not suitable for mass screening, we aimed to characterize the predictive utility of tumour morphology and ALK immunoreactivity to identify ALK rearrangement, in a primary lung adenocarcinoma dataset enriched for signet-ring morphology, compared with that of other morphology. METHODS: 7 adenocarcinomas from diagnostic archives reported with signet-ring morphology were assessed and compared with 11 adenocarcinomas without signet-ring features over the same time period. Growth patterns were reviewed, ALK expression was assessed by standard immunohistochemistry using ALK1 clone and Envision detection (Dako), and ALK rearrangement was assessed by FISH (Abbott Molecular). Associations between groups and predictive utility of tumour morphology and ALK expression using FISH as gold standard were calculated. RESULTS: 2 excision lung biopsy cases with pure (100%) signet-ring morphology and solid patterns demonstrated diffuse moderate cytoplasmic ALK immunoreactivity (2+) and harboured ALK rearrangements (p=0.007), unlike 5 mixed-signet-ring and 11 non-signet-ring adenocarcinomas, which showed negative or 1+ immunoreactivity; and did not harbour ALK rearrangements (p>0.1). ALK expression was not associated with ALK copy number. 6 of 7 cases with signet ring morphology stained for TTF-1. Pure signet-ring morphology and moderate ALK expression were both associated with ALK rearranged tumours. CONCLUSION: ALK rearrangement is strongly associated with ALK immunoreactivity, and was seen only in tumours with pure signet-ring morphology and solid growth pattern. Tumour morphology, growth pattern and ALK immunoreactivity appear to be good indicators of ALK rearrangement, with TTF-1 positivity aiding in proving primary pulmonary origin.

Fluorescence in situ hybridization methods and troubleshooting applied to fixed cell suspensions.

A robust procedure for performing fluorescence in situ hybridization (FISH) is described, with tips for troubleshooting. FISH probes are now more reliable and there is a greater range commercially available. FISH is an essential part of the cytogeneticist's repertoire. It remains a powerful, complementary adjunct to karyotype studies, and knowledge of the underlying chromosome abnormalities can be essential for understanding the FISH signal patterns.

Primary pulmonary myxoid sarcoma with EWSR1-CREB1 fusion: a new tumor entity.

We present clinicopathologic data on 10 pulmonary myxoid sarcomas, which are defined by distinctive histomorphologic features and characterized by a recurrent fusion gene, that appear to represent a distinct tumor entity at this site. The patients [7 female, 3 male; aged 27 to 67 y (mean, 45 y)] presented with local or systemic symptoms (n=5), symptoms from cerebral metastasis (1), or incidentally (2). Follow-up of 6 patients showed that 1 with brain metastasis died shortly after primary tumor resection, 1 developed a renal metastasis but is alive and well, and 4 are disease free after 1 to 15 years. All tumors involved pulmonary parenchyma, with a predominant endobronchial component in 8 and ranged from 1.5 to 4 cm. Microscopically, they were lobulated and composed of cords of polygonal, spindle, or stellate cells within myxoid stroma, morphologically reminiscent of extraskeletal myxoid chondrosarcoma. Four cases showed no or minimal atypia, 6 showed focal pleomorphism, and 5 had necrosis. Mitotic indices varied, with most tumors not exceeding 5/10 high-power fields. Tumors were immunoreactive for only vimentin and weakly focal for epithelial membrane antigen. Of 9 tumors, 7 were shown to harbor a specific EWSR1-CREB1 fusion by reverse transcription-polymerase chain reaction and direct sequencing, with 7 of 10 showing EWSR1 rearrangement by fluorescence in situ hybridization. This gene fusion has been described previously in 2 histologically and behaviorally different sarcomas: clear cell sarcoma-like tumors of the gastrointestinal tract and angiomatoid fibrous histiocytomas; however, this is a novel finding in tumors with the morphology we describe and that occur in the pulmonary region.

Utility of sarcoma-specific fusion gene analysis in paraffin-embedded material for routine diagnosis at a specialist centre.

AIMS: Diagnosis of soft tissue sarcomas can be difficult. It can be aided by detection of specific genetic aberrations in many cases. This study assessed the utility of a molecular genetics/cytogenetics service as part of the routine diagnostic service at the Royal Marsden Hospital. METHODS: A retrospective audit was performed over a 15-month period to evaluate the diagnostic usefulness for soft tissue sarcomas with translocations of fluorescence in situ hybridisation (FISH) and reverse-transcriptase PCR (RT-PCR) in paraffin-embedded (PE) material. Results were compared with histology, and evaluated. RESULTS: Molecular investigations were performed on PE material in 158 samples (total 194 RT-PCR and 174 FISH tests), of which 85 were referral cases. Synovial sarcoma, Ewing sarcoma and low-grade fibromyxoid sarcoma were the most commonly tested tumours. Myxoid liposarcoma showed the best histological and molecular concordance, and alveolar rhabdomyosarcoma showed the best agreement between methods. FISH had a higher sensitivity for detecting tumours (73%, compared with 59% for RT-PCR) with a better success rate than RT-PCR, although the latter was specific in identifying the partner gene for each fusion. In particular, referral blocks in which methods of tissue fixation and processing were not certain resulted in higher RT-PCR failure rates. CONCLUSIONS: FISH and RT-PCR on PE tissue are practical and effective ancillary tools in the diagnosis of soft tissue sarcomas. They are useful in confirming doubtful histological diagnoses and excluding malignant diagnoses. PCR is less sensitive than FISH, and the use of both techniques is optimal for maximising the detection rate of translocation-positive sarcomas.

Primary Adult Renal Ewing's Sarcoma: A Rare Entity.

Background. Ewing's sarcoma of extraskeletal origin is uncommon and that is of primary renal origin in adults are rare. There is no consensus on the optimal management of Ewing's tumors of renal origin. Methods. A retrospective review of the clinical features, treatment, and outcome of adult patients with primary renal extra-skeletal Ewing's sarcoma who were treated at the Royal Marsden hospital from January 1993-December 2007 is reported. Results. Seven adult patients with primary renal Ewing's sarcoma were identified. All four patients with nonmetastatic disease had radical nephrectomy and received adjuvant chemotherapy +/- radiotherapy. Two developed metastatic disease while on adjuvant chemotherapy, and one patient relapsed after 55 months. The three patients with metastatic disease at presentation did not have nephrectomy and were treated with chemotherapy. All three patients had disease progression with a dismal outcome. Only one patient in the whole group is alive and disease free. The median overall survival was 62.8 months, and the median disease-free survival in patients with nonmetastatic disease after combined modality treatment was 30.3 months. Conclusion. Primary adult renal Ewing's sarcoma is an aggressive tumor with a propensity for early metastasis. Radical nephrectomy with adjuvant combination chemotherapy produced the best results but the outlook remained poor with only one patient experiencing long disease-free survival.