ObjectiveTo study the clinical, pathologic, and genetic features of thymic carcinoids in the setting of multiple endocrine neoplasia type 1 (MEN1) and to study means for detection and prevention of this tumor in patients with MEN1. Summary Background DataThymic carcinoid is a rare malignancy, with approximately 150 cases reported to date. It may be associated with MENW and carries a poor prognosis, with no effective treatment. Its underlying etiology is unknown. MethodsTen patients with MEN1 from eight famifles with anterior mediastinal tumors were induded in a case senes study at terkary referring hospitals. Clinicopathologic studies were done on these patients, with a review of the literature. Mutation analysis was performed on the MEN1 gene in families with dusterings of the tumor to look for genotype-phenotype correlation. Loss of heterozygosity was studied in seven cases to look for genetic abnormalities. ResultsHistologic studies of all tumors were consistent with the diagnosis of thymic carcinoid. Clustering of this tumor was found in some of the families-three pairs of brothers and three families with first-or second-degree relatives who had thymic carcinoid. ConclusionsMEN1 -related thymic carcinoids constitute approximately 25% of all cases of thymic carcinoids. In patients with MEN1, this is an insidious tumor not associated with Cushing's or carcinoid syndrome. Local invasion, recurrence, and distant metastasis are common, with no known effective treatment. We propose that CT or MRI of the chest, as well as octreoscanning, should be considered as part of dinical screening in patients with MEN1. We also propose performing prophylactic thymectomy during subtotal or total parathyroidectomy on patients with MEN1 to reduce the risks of thymic carcinoid and recurrence of hyperparathyroidism. Its male predominance, the absence of LOH in the MEN1 region, clustering in dose relatives, and the presence of dfferent MEN1 mutations in these families suggest the involvement of moding genes in additin to the MEN1 gene. A putative tumor suppressor gene in 1 p may be involved.

T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive neoplasm of mature T-cells with an urgent need for rationally designed therapies to address its notoriously chemo-refractory behavior. The median survival of T-PLL patients is <2 years and clinical trials are difficult to execute. Here we systematically explored the diversity of drug responses in T-PLL patient samples using an ex vivo drug sensitivity and resistance testing platform and correlated the findings with somatic mutations and gene expression profiles. Intriguingly, all T-PLL samples were sensitive to the cyclin-dependent kinase inhibitor SNS-032, which overcame stromal-cell-mediated protection and elicited robust p53-activation and apoptosis. Across all patients, the most effective classes of compounds were histone deacetylase, phosphoinositide-3 kinase/AKT/mammalian target of rapamycin, heat-shock protein 90 and BH3-family protein inhibitors as well as p53 activators, indicating previously unexplored, novel targeted approaches for treating T-PLL. Although Janus-activated kinase-signal transducer and activator of transcription factor (JAK-STAT) pathway mutations were common in T-PLL (71% of patients), JAK-STAT inhibitor responses were not directly linked to those or other T-PLL-specific lesions. Overall, we found that genetic markers do not readily translate into novel effective therapeutic vulnerabilities. In conclusion, novel classes of compounds with high efficacy in T-PLL were discovered with the comprehensive ex vivo drug screening platform warranting further studies of synergisms and clinical testing.

Multicolor fluorescent in situ hybridization (FISH) was used to identify acquired chromosomal aberrations in 12 patients with mycosis fungoides or Sézary syndrome, the most common forms of primary cutaneous T-cell lymphoma (CTCL). The most frequently affected chromosome was 12, which showed clonal deletions or translocations with a break point in 12q21 or 12q22 in five of seven consecutive Sézary syndrome patients and a clonal monosomy in the sixth patient. The break point of a balanced translocation t(12;18)(q21;q21.2), mapped in the minimal common region of two deletions, fine mapped to 12q2. By locus-specific FISH, the translocation disrupted one gene, NAV3 (POMFIL1), a human homologue of unc-53 in Caenorhabditis elegans. A missense mutation in the remaining NAV3 allele was found in one of six cases with a deletion or translocation. With locus-specific FISH, NAV3 deletions were found in the skin lesions of four of eight (50%) patients with early mycosis fungoides (stages IA-IIA) and in the skin or lymph node of 11 of 13 (85%) patients with advanced mycosis fungoides or Sézary syndrome. Preliminary functional studies with lentiviral small interfering RNA-based NAV3 silencing in Jurkat cells and in primary lymphocytes showed enhanced interleukin 2 expression (but not CD25 expression). Thus, NAV3 may contribute to the growth, differentiation, and apoptosis of CTCL cells as well as to the skewing from Th1-type to Th2-type phenotype during disease progression. NAV3, a novel putative haploinsufficient tumor suppressor gene, is disrupted in most cases of the commonest types of CTCL and may thus provide a new diagnostic tool. (Cancer Res 2005; 65(18): 8101-10)

The aim of the study was to detect mutations of BRAF oncogene in colorectal cancer and to use this information to identify Lynch syndrome patients. Consecutive cases of primary colorectal cancer (n = 137) were analyzed for MLH1 protein expression using immunohistochemistry (IHC). BRAF V600E mutation was detected by IHC using a specific monoclonal antibody (VE1) and by qPCR. All MLH1 protein-negative cases were subjected to microsatellite instability analysis and MLH1 promoter methylation assay. MLH1 protein expression deficiency and high microsatellite instability (MSI-H) were detected in 18 of the 137 (13.1%) consecutive colorectal cancer specimens. Detection of the BRAF V600E mutation by IHC was 100% sensitive and specific as compared to qPCR, and this mutation was frequently present in the MSI-H group (77.8%; 14/18) and less frequently in the microsatellite-stable group (7.6%; 9/118). All BRAF V600E mutated cases of the MSI-H group presented with a MLH1 promoter methylation (14/14) as detected by methylation-specific multiplex ligation-dependent probe amplification. When BRAF was wild type in the MSI-H group, only one MLH1 promoter methylation was detected (1/4), and of the remaining three cases without MLH1 methylation, two were identified to harbor an MLH1 mutation consistent with Lynch syndrome. Finally, 11 previously confirmed Lynch syndrome cases were analyzed for BRAF V600E mutation, and all of them were wild type. In conclusion, detection of BRAF V600E in colorectal cancer specimens by IHC is sensitive and specific and may help to identify Lynch syndrome patients.

Objective: The existence of genotype-phenotype correlation in multiple endocrine neoplasia type 1 (MEN1) is controversial. Two founder mutations of the MEN1 gene in Northern Finland gave us an opportunity to compare clinical features among heterozygotes of different mutations. Results: Founder mutations 1466del12 and 1657insC were found in 39 and 29 individuals, and D418N, G156R and R527X mutations in 9, 3 and 2 individuals respectively. Except for pituitary adenoma and nonfunctional pancreatic tumour (NFPT), age was a risk factor for all the disease manifestations. For NFPT, frameshift/nonsense mutations (1657insC, R527X) gave an odds ratio (OR) of 3.26 (95% confidence intervals (CI), 1.27-8.33; PZ0.014) compared with in-frame/missense mutations (1466del12, D418N, G156R); including the founder mutation carriers (nZ68) only, the 1657insC mutation gave an OR of 3.56 (CI, 1.29-9.83; PZ0.015). For gastrinoma, in-frame/missense mutations predicted the risk with an OR of 6.77 (CI, 1.31-35.0; PZ0.022), and in the founder mutations group the 1466del12 mutation gave an OR of 15.09 (CI, 1.73-131.9, PZ0.014).

We have characterized the cytogenetic alterations of the human embyronal cell line 293 by spectral karyotyping and G-banding analysis. To investigate its genomic stability, we compared the karyotypes of 293 and its daughter line EcR-293. Genotype profiling through short tandem repeats complemented the analysis. While displaying almost identical STR profiles and thus verifying their origin and their close relation, the two lines were remarkably different in their number of chromosomes and setup of aberrant chromosomes. However, the cell lines retained a stable karyotype in long term culture. The establishment of subclones from EcR-293, expressing inducible lacZ or MEN1 transgenes, only added minor changes to the karyotype. Our study shows that the cytogenetic constitution of a clonal cell line of the 293 origin appears to be sufficiently stable. However, care should be taken when comparing the properties of independent 293 lineages, since clonal variations might be substantial.

Carcinoid tumors are rare neuroendocrine tumors occurring in the lung or in the digestive tract where they are further subclassified as foregut, midgut, or hindgut carcinoids. To gain a better understanding of the genetic basis of the different types of carcinoid tumors, we have characterized numerical imbalances in a series of midgut carcinoids, and compared the results to previous findings in carcinoids from the lung. Numerical imbalances were revealed in 16 of the 18 tumors, and the most commonly detected aberrations were losses of 18q22-qter (67%), 11q22-q23 (33%), and 16q21-qter (22%), and gain of 4p14-qter (22%). The total number of alterations found in the metastases was significantly higher than in the primary tumors, indicating the accumulation of acquired genetic changes in the tumor progression. Losses of 18q and 11q were present both in primary tumors and metastases, whereas loss of 16q and gain of 4 were only detected in metastases. Furthermore, the pattern of comparative genomic hybridization alterations varied depending on the total number of detected alterations. Taken together, the findings would suggest a progression of numerical imbalances, in which loss of 18q and 11q represent early events, and loss of 16q and gain of 4p are late events in the tumor progression of midgut carcinoids. When compared to previously published comparative genomic hybridization abnormalities in lung carcinoids, loss of 11q was found to occur in both tumor types, whereas loss of 18q and 16q and gain of 4 were not revealed in lung carcinoids. The results indicate that inactivation of a putative tumor suppressor gene in 18q22-qter represents a frequent and early event that is specific for the development of midgut carcinoids.

We describe a family in which seven members in three generations were affected with a rare spinal neurofibromatosis. The affected adults showed, at the ages of 32, 37, 38, and 61, respectively, multiple spinal neurofibromas symmetrically affecting all spinal roots. Two patients were operated on for histopathologically proven cervical spinal neurofibromas. All patients had cafe au lait spots, one had several freckles in the axillary area, and two had possible dermal neurofibromas, but iris Lisch nodules were not present. Other signs of neurofibromatosis types 1 and 2 were absent. A linkige study of the family suggested close linkage to the NF1 locus and excluded it from the NF2 locus. The DNA analysis of histopathologically verified spinal neurofibromas in two patients showed no evidence of LOH at 17ql1.2.The findings in the present family, together with those in a family previously described, suggest a clinically distinct form of neurofibromatosis with extensive spinal neurofibromas and cafe au lait macules, which may be allelic to the NFI gene. (JMed Genet 1997;34:184-187