Tse Hui Lim

Dasatinib Induces a Response in Malignant Thymoma

TO THE EDITOR: Dasatinib is a novel, oral, multitargeted kinase inhibitor of Bcr-Abl and Src family kinases, as well as ephrin receptor kinases, platelet-derived growth factor receptor, and c-Kit. It was recently shown to be effective in inducing hematologic and cytogenetic responses in imatinib-resistant BCR-ABL-positive leukemias. Preclinical studies have also revealed that dasatinib has activity in head and neck, lung, pancreatic, and prostate cancer cells, raising the possibility that dasatinib may have a wider spectrum for other clinical diseases. We report, in this letter, the first clinical case of a dasatinibresponsive thymoma. The patient was diagnosed with chronic myeloid leukemia in 1994 and developed lymphoid blast crisis in 2003 after interferon-alfa therapy. He was treated with imatinib and conventional chemotherapy and achieved a complete cytogenetic remission (CCR). He was maintained on imatinib and remained in CCR. In October 2005, he developed another lymphoid blast crisis with white cell counts of 17,840/mm, blasts 86%, hemoglobin 5.9 g/dL, and platelet counts of 5,000/mm. Direct sequencing of the Abl kinase revealed the Y253H mutation. A chest x-ray showed a left hilar mass and left pleural effusion. Computer tomography (CT) of the thorax confirmed the presence of the anterior mediastinal mass with a volumetric measurement of 69.3 cm. Cytologic examination of the effusion revealed a predominant lymphocytic yield. Severe thrombocytopenia precluded a biopsy of the mass. He was enrolled onto the local internal review board approved phase II dasatinib clinical trial and started on 140 mg daily in November 2005. Two months after dasatinib, he achieved a complete hematologic and cytogenetic remission. CT of the thorax showed a partial resolution in the size of the mediastinal mass (40.6 cm) but worsening of the pleural effusion, a possible dasatinib-related adverse effect (Fig 1). His thrombocytopenia had resolved and a thoracotomy was performed to drain the pleural fluid and the mass was completely resected. The thymic tumor (Fig 2A) featured lobular, organotypic proliferation of neoplastic epithelial cells, with large vesicular nuclei and prominent nucleoli, admixed with a background population of small lymphocytes. There were occasional perivascular spaces and scattered macrophages. Cystic degeneration accompanied by hemorrhage and siderophages was prominently displayed. Although there were lymphocyte poor areas where the tumor cells appeared to form more confluent sheets, the nuclear features remained those of B2-type. The tumor had infiltrated into but not through the capsule (modified Masaoka stage I). Leukemic infiltrates were not seen. The tumor cells were evaluated for their cell membrane reactivity with epidermal growth factor receptor (EGFR) using the anti-EGFR mouse monoclonal antibody (clone E30; DakoCytomation, Glostrup, Denmark). The guidelines of the College of American Pathologists for HER2/cerb-B2 were used to grade EGFR membrane expression. EGFR cell membrane staining of a score of 1 (faint incomplete) to 2 (moderate but complete) was detected in 20% of the tumor cells (Fig 2B). The

Gefitinib, cisplatin, and concurrent radiotherapy for locally advanced head and neck cancer: EGFR FISH, protein expression, and mutational status are not predictive biomarkers

BACKGROUNDnGefitinib was demonstrated to be synergistic with cisplatin and radiotherapy (RT) in in vitro studies. Biomarkers predictive of response to gefitinib in squamous cell head and neck cancer is still lacking.nnnMETHODSnThirty-one patients with locally advanced and easily accessible primary tumor sites for biopsies were recruited. Gefitinib was started 3 weeks before the start of cisplatin/concurrent radiotherapy (CTRT) and continued during the CTRT phase and thereafter for 4 months as consolidation phase. Two baselines and a repeat tumor sample were taken after 2 weeks of gefitinib alone to study its impact on tumor gene expression. Epidermal growth factor receptor (EGFR) protein expression, FISH and mutational status, and matrix metallopeptidase 11 (MMP11) protein expression were correlated with response and survival outcome.nnnRESULTSnThe overall response rate to gefitinib alone was 9.7%. The survival outcome is as follows: median disease free 1.3 years, median survival time 2.4 years, 3-year disease free 42.9%, and 3-year overall survival 48.4%. EGFR FISH, protein expression, and mutational status did not predict for response nor survival outcome of patients. Although MMP11 overexpression did not predict for response, it predicted significantly for a poorer survival outcome.nnnCONCLUSIONSnGefitinib can be combined safely with cisplatin/RT. More studies are needed to uncover predictive biomarkers of benefit to gefitinib.

Occurrence of trisomy 12, t(14;18)(q32;q21), and t(8;14)(q24.1;q11.2) in a patient with B-cell chronic lymphocytic leukemia

Trisomy 12, t(14;18)(q32;q21), and t(8;14)(q24.1;q11.2) were found in a 59-year-old man with B-cell chronic lymphocytic leukemia (CLL). While trisomy 12 is one of the most common cytogenetic abnormalities in chronic lymphocytic leukemia, the t(14;18) rearrangement has a strong association with follicular lymphoma and the t(8;14) is associated with T-cell neoplasia. Occurrence of these three abnormalities in CLL are rare, and the significance of this finding is unclear. Further studies of similar cases may shed additional insight into this finding.

Characterization and therapeutic evaluation of a Nestin+ CNP+ NG2+ cell population on mouse spinal cord injury

The NG2 chondroitin sulfate proteoglycan-expressing neural cells (NG2 cells) have originally been considered as oligodendrocyte progenitor cells (OPCs). However, recent findings on their diverse functions and lineage heterogeneity demonstrated that the NG2 cells contain various sub-populations whose concrete features and therapeutic potential yet remained elucidated. In the present study, we characterized a Nestin(+) 2,3-cyclic nucleotide 3-phosphodiesterase (CNP)(+) NG2(+) subpopulation from embryonic rat cerebral cortex. The Nestin(+) CNP(+) NG2(+) cells exhibited remarkable progenitor characteristics. Having been immortalized by human telomerase reverse transcriptase (hTERT), the life span of Nestin(+) CNP(+) NG2(+) cells was extended to 230 population doublings (PDs). With immortalized NG2 cells, we demonstrated their differentiation capacities to oligodendrocytes, astrocytes and neurons. Furthermore, transplanted into injured spinal cord of a mouse model, they were able to promote remyelination and neuronal regeneration, thereby enhancing the functional recovery. Our findings suggest that the Nestin(+) CNP(+) NG2(+) progenitor cells could be a good alternative cell source of cell therapy for neurological disorders.

CpG Oligonucleotide and Interleukin 2 stimulation enables higher cytogenetic abnormality detection rates than 12-o-tetradecanolyphorbol-13-acetate in Asian patients with B-cell chronic lymphocytic leukemia (B-CLL)

Abstract The present study was designed to compare abnormality detection rates using DSP30xa0+xa0IL2 and 12-O-Tetradecanoylphorbol-13-acetate (TPA) in Asian patients with B-CLL. Hematological specimens from 47 patients (29 newly diagnosed, 18 relapsed) were established as 72xa0h-DSP30xa0+xa0IL2 and TPA cultures. Standard methods were employed to identify clonal aberrations by conventional cytogenetics (CC). The B-CLL fluorescence in situ hybridization (FISH) panel comprised ATM, CEP12, D13S25, and TP53 probes. DSP30xa0+xa0IL2 cultures had a higher chromosomal abnormality detection rate (67xa0%) compared to TPA (44xa0%, pxa0<xa00.001). The mean number of analyzable metaphases and abnormal metaphases per slide was also higher (pxa0<xa00.005, pxa0<xa00.001, respectively). Culture success rate, percentage of complex karyotype, and percentage of non-clonal abnormal cell were not significantly different (pxa0>xa00.05). Thirteen cases with abnormalities were found exclusively in DSP30xa0+xa0IL2 cultures compared to one found solely in TPA cultures. DSP30xa0+xa0IL2 cultures were comparable to the FISH panel in detecting 11q−, +12 and 17p− but not 13q−. It also has a predilection for 11q− bearing leukemic cells compared to TPA. FISH had a higher abnormality detection rate (84.1xa0%) compared to CC (66.0xa0%) with borderline significance (pxa0=xa00.051), albeit limited by its coverage. In conclusion, DSP30xa0+xa0IL2 showed a higher abnormality detection rate. However, FISH is indispensable to circumvent low mitotic indices and detect subtle abnormalities

Chromosome 1q21.3 amplification is a trackable biomarker and actionable target for breast cancer recurrence

Tumor recurrence remains the main reason for breast cancer–associated mortality, and there are unmet clinical demands for the discovery of new biomarkers and development of treatment solutions to benefit patients with breast cancer at high risk of recurrence. Here we report the identification of chromosomal copy-number amplification at 1q21.3 that is enriched in subpopulations of breast cancer cells bearing characteristics of tumor-initiating cells (TICs) and that strongly associates with breast cancer recurrence. Amplification is present in ∼10–30% of primary tumors but in more than 70% of recurrent tumors, regardless of breast cancer subtype. Detection of amplification in cell-free DNA (cfDNA) from blood is strongly associated with early relapse in patients with breast cancer and could also be used to track the emergence of tumor resistance to chemotherapy. We further show that 1q21.3-encoded S100 calcium-binding protein (S100A) family members, mainly S100A7, S100A8, and S100A9 (S100A7/8/9), and IL-1 receptor–associated kinase 1 (IRAK1) establish a reciprocal feedback loop driving tumorsphere growth. Notably, this functional circuitry can be disrupted by the small-molecule kinase inhibitor pacritinib, leading to preferential impairment of the growth of 1q21.3-amplified breast tumors. Our study uncovers the 1q21.3-directed S100A7/8/9–IRAK1 feedback loop as a crucial component of breast cancer recurrence, serving as both a trackable biomarker and an actionable therapeutic target for breast cancer.

Clear cell sarcomas of kidney are characterized by BCOR gene abnormalities including exon 15 internal tandem duplications and BCOR-CCNB3 gene fusion

Clear cell sarcoma of the kidney (CCSK) is a rare paediatric renal malignant tumour. The majority of CCSKs have internal tandem duplications (ITDs) of the BCOR gene, whereas a minority have the YWHAE–NUTM2 gene fusion. A third ‘double‐negative’ (DN) category comprises CCSKs with neither BCOR ITDs nor YWHAE–NUTM2 fusion. The aim of this study was to characterise 11 histologically diagnosed CCSKs immunohistochemically (with CCND1, BCOR and CCNB3 stains) and genetically.

Fluorescence In Situ Hybridization on Tissue Sections

Formalin-fixed paraffin-embedded (FFPE) tissues are typically the specimens available for FISH analysis of solid tissues, particularly of tumor specimens. Occasionally, tissue cores constructed as tissue microarrays from several patients are presented for simultaneous evaluation. FFPE sections can also be prepared from cell blocks derived from cell suspensions. The interphase fluorescence in situ hybridization assay employs specific nucleic acid sequences (probes) that target complementary sequences of interest to detect gains or losses of genes/gene loci or a fusion gene within the tissue. In this chapter, we describe the protocols utilized in our laboratory and include slide deparaffinization, pretreatment, protease treatment, hybridization, washing, and counterstaining. This protocol can be applied to all of the earlier FFPE preparations. In general, the assay takes 3 consecutive days to complete, although a more rapid assay can be performed.

Amplification of 1q21 and Other Abnormalities in Multiple Myeloma Patients from a Tertiary Hospital in Singapore

Much effort has been made to stratify multiple myeloma patients for targeted therapy. However, responses have been varied and improved patient stratifications are needed. Forty-five diagnostic samples from multiple myeloma patients (median age 65xa0years) were stratified cytogenetically as 15 having non-hyperdiploidy, 20 having hyperdiploidy and 10 having a normal karyotype. Fluorescence in situ hybridization (FISH) assays with FGFR3/IGH, CCND1/IGH, IGH/MAF, RB1 and TP53 probes on bone marrow samples showed that IGH rearrangements were the most common abnormality in the non-hyperdiploid group but these were also found among hyperdiploid patients and patients with normal cytogenetics. Of these, FGFR3/IGH rearrangements were most frequent. Deletion of RB1/monosomy 13 was the most common genetic abnormality across the three groups and was significantly higher among non-hyperdiploid compared to hyperdiploid patients. On the other hand, the study recorded a low incidence of TP53 deletion/monosomy 17. The FGFR3/IGH fusion was frequently seen with RB1 deletion/monosomy 13. FISH with 1p36/1q21 and 6q21/15q22 probes showed that amplification of 15q22 was seen in all of the hyperdiploid patients while amplification of 1q21, Amp(1q21), characterized non-hyperdiploid patients. In contrast, deletions of 1p36 and 6q21 were very rare events. Amp(1q21), FGFR3/IGH fusion, RB1 deletion/monosomy 13, and even TP53 deletion/monosomy 17 were seen in some hyperdiploid patients, suggesting that they have a less than favorable prognosis and require closer monitoring.

Spindle Cell Lipoma in an End-Stage Renal Allograft: Case Report

BACKGROUNDnSpindle cell lipoma is an uncommon variant of lipoma and usually occurs as a solitary, subcutaneous, and well circumscribed lesion in the posterior neck, shoulders, and back of older men. Primary renal lipomas are rarely reported. Spindle cell lipoma in the kidney has not been previously described in the literature.nnnCASE REPORTnA 60-year-old Chinese man suffered graft failure 10 years after living related donor kidney transplantation. During cancer surveillance, he was found to have a mass in the renal allograft, which increased in size and was suspicious for renal cell carcinoma on computerized tomographic scan. The patient underwent renal graft explantation. Grossly, the kidney was atrophic, containing a 6.5 cm yellowish solid lesion without hemorrhage and necrosis in the renal sinus fat. Microscopically, the lesion was composed of variably sized adipocytes and cellular areas of bland spindle cells with no cytologic atypia. There were prominent slender blood vessels within the lesion, along with focal myxoid change as well as scattered mast cells and inflammatory cells. Lipoblasts were not identified. The spindle cells were positive for CD34 and negative for Melan-A, HMB45, S100, and SMA. Pax-2 stain was nonspecific. MDM2 amplification by means of fluorescence in situ hybridization (FISH) and overexpression by immunohistochemistry were negative. The Ki-67 proliferation index wasxa0<1%. Interphase FISH revealed loss of 13q and 16q in the tumor.nnnCONCLUSIONSnRenal spindle cell lipoma is a rare benign tumor. Angiomyolipoma and well differentiated liposarcoma are the main differential diagnoses. Immunohistochemistry and cytogenetic techniques are helpful in differentiating it from malignant entities.