Comparative genomic hybridization (CGH) using 40 cell lines derived from malignant melanomas (MMs) revealed frequent amplification at 7q33-q34 containing BRAF gene, which often is mutated in MM. We found this gene to be amplified to a remarkable degree in the MM cell lines that exhibited high-level gains at 7q33-q34 in CGH. Among 40 cell lines, the eight lines that revealed neither BRAF nor NRAS mutations showed even higher levels of BRAF mRNA expression than the 32 mutated lines, although DNA amplification at 7q33-q34 was not detected in every lines overexpressing BRAF. MM cells that carried wild-type BRAF and NRAS showed constitutive overexpression of B-Raf protein and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), even after serum starvation. Not only downregulation of the endogenously overexpressed wild-type B-Raf by antisense oligonucleotide but also a treatment with an inhibitor of mitogen-activated protein kinase kinase (MAPKK, MEK) reduced phosphorylated ERK1/2 and cell growth, whereas the exogenously expressed wild-type B-Raf promoted cell growth in MM cells. Our results provide the evidence that overexpression of wild-type B-Raf, in part but not always as a result of gene amplification, is one of the mechanisms underlying constitutive activation of the MAPK pathway that stimulates growth of MM cells.

BACKGROUND The management of occult cervical lymph node metastases originating from oral squamous cell carcinomas (OSCCs) remains controversial. The purpose of this study was to evaluate the value of cyclin D1 gene (CCND1) numerical aberrations in predicting the risk of late lymph node metastases. METHODS Fluorescence in situ hybridization (FISH), using a BAC clone specific for CCND1, was performed on OSCC specimens obtained by fine‐needle aspiration (FNA) biopsy from 45 patients with previously untreated TNM Stage I and II (T1‐2N0M0) disease who had not undergone elective cervical lymph node dissection. RESULTS CCND1 numerical aberrations were observed in 15 (33.3%) of the 45 patients and were significantly associated with the mode of invasion of the primary tumor (P = 0.01) and the presence of occult lymph node metastases (P < 0.001). Twelve of these 15 patients (80%) developed late cervical lymph node metastases within 2 years of surgery for primary OSCCs. All patients with cluster‐type amplification of CCND1 developed late lymph node metastases. Multivariate analysis showed that only CCND1 numerical aberrations (risk ratio, 8.685%, 95% confidence interval = 2.232–33.802, P = 0.002) independently predicted late cervical lymph node metastasis. CONCLUSIONS Aberrations in CCND1 numbers appear to be valuable in identifying patients at high risk of late lymph node metastasis in Stage I and II OSCCs. Analysis of CCND1 numerical aberrations using FISH on FNA biopsy specimens may be useful in selecting patients for elective cervical lymph node dissection. Cancer 2005. © 2005 American Cancer Society.

We describe the clinical features and MRimaging findings of spontaneous spinal subarachnoid hemorrhage located in the lumbar spine associated with subdural hematoma at a higher, thoracic level in a 66-yearold man without neurological deficit. The sequential MRimaging changes of hemorrhage at various stages in its evolution are portrayed. The possible pathogenetic mechanism for these very unusual, combined hemorrhages in both spinal compartments is discussed.Keywords Spontaneous . Subarachnoid hemorrhage . Subdural hematoma . Spine . MRI Case reportA 66-year-old man presented to the emergency department with history of 1 week of lower back pain, headache, and left lower limb pain. He had no history of trauma, physical exertion, anticoagulant therapy, or any known bleeding dyscrasias. The patient had a fever of 100°F. He did not develop paraparesis, loss of sensation, numbness or urinary dysfunction. Physical examination disclosed localized tenderness over the lumbar spine. Neurologic examination was normal. Pertinent laboratory data were within normal limits except for mild elevation of lactate dehydrogenase (262 IU/l).Urgent CT scan of the head showed no evidence of subarachnoid or intracerebral hemorrhage. MR imaging of the spine performed on the same day of admission demonstrated a linear subarachnoid lesion extending from L1 to L5, ventral to the conus medullaris and cauda equina. The subarachnoid process was of increased signal intensity relative to the spinal cord on both T1-and T2-weighted images; which was suggestive of subacute hemorrhage (Fig. 1). In addition, a subdural lesion with a smooth contour was seen extending from T11 to T12 vertebrae and overlying the ventrolateral aspect of the spinal canal. This abnormal area displayed predominantly increased signal intensity relative to the spinal cord on T1-weighted images. On T2-weighted images, the lesion showed heterogeneously increased signal intensity with a focus of low signal intensity compatible with subacute hematoma containing deoxyhemoglobin (Fig. 2). The subdural hematoma was compressing the adjacent spinal cord without obvious signal changes within the cord. No MR-imaging evidence of vascular abnormalities was visualized in the spine. Although the patient was advised to undergo spinal angiography, he did not consent to.

The most common nonrandom translocation found among childhood pre-B acute lymphoblastic leukemias (ALL) is t(1;19)(q23;p13), which frequently results in fusion of E2A with PBX1. However, rare cases of childhood ALL and various other hematological diseases with t(1;19) lack the E2A-PBX1 fusion. Analyzing a cell line with pre-B-cell phenotype, TS-2, that carries t(1;19)(q23;p13) but lacks the E2A-PBX1 fusion, we successfully cloned the breakpoints, which fell within introns of MEF2D and DAZAP1. Both chimeric transcripts, MEF2D-DAZAP1 and DAZAP1-MEF2D, whose sequences indicated in-frame fusions between MEF2D and DAZAP1, were expressed in TS-2 cells and in bonemarrow cells of the patient from whom the TS-2 was established. MEF2D-DAZAP1 and DAZAP1-MEF2D proteins were both located in the nucleus, and MEF2D-DAZAP1 was able to form dimers with MEF2D and HDAC4. In addition, exogenous expression of MEF2D-DAZAP1 and DAZAP1-MEF2D promoted the growth of HeLa cells. Given the frequency of t(1;19) without the E2A-PBX1 fusion in hematological malignancies, we suggest that MEF2D/DAZAP1 rearrangements might be involved in the pathogenesis of those diseases. (Cancer Sci 2004; 95: 503-507) he most common type of childhood leukemia is acute lymphoblastic leukemia (ALL), which has a B-cell precursor phenotype.1) The main subtypes of ALL involve multiple genetic alterations including point mutations and deletions, and are also characterized by gross chromosomal changes such as translocations, which are likely to cause illegitimate recombination or juxtaposition of normally separated genes. In leukemias an in-frame fusion gene is often created, generating a hybrid protein with altered properties. Although more than 200 genes are known to be involved in translocations in leukemias, certain genes predominate in those events and the others are involved only rarely. 1)The most common nonrandom translocation in childhood pre-B ALL is t(1;19)(q23;p13), usually involving fusion between PBX1 at 1q23 and E2A at 19p13.3. The chimeric gene, E2A-PBX1, encodes a protein that contains the transactivation domain of E2A and the DNA-binding homeodomain of PBX1. 2)Although an identical E2A-PBX1 chimeric gene can be detected in more than 95% of ALL cases with t(1;19), in rare cases the E2A-PBX1 fusion gene is absent. 3,4)

Although the vacuum disc is considered a common imaging finding of no or not much pathologic significance, occasionally intradiscal gas may leak into the spinal canal. Detection of an epidural gaseous collection at the same level with a vacuum disc strongly suggests a communication between the intervertebral disc and the epidural space. Epidural gas collections can be implicated as a possible cause of radicular symptoms and should be considered in the differential diagnosis of lumbar radiculopathy.