Extensive molecular screening for hereditary non-polyposis colorectal cancer

The genetic abnormalities underlying hereditary non-polyposis colorectal cancer (HNPCC) are germline mutations in one of five DNA mismatch repair genes or in the TGFβRII gene. The aim of our study was to evaluate the significance of simple tests performed on tumours to select appropriate candidates for germline mutational analysis. We studied three groups of patients, HNPCC kindreds fulfilling the International Collaborative Group (ICG) criteria (n = 10), families in which at least one of the criteria was not satisfied (n = 7) and sporadic colorectal cancer (CRC) diagnosed before the age of 50 (n = 17). We searched for microsatellite instability (MSI), presence of hMSH2 and hMLH1 germline mutations, expression of hMSH2, hMLH1 and p53 proteins in tumoural tissue samples by immunostaining. Fifteen out of 17 (88%) of HNPCC and incomplete HNPCC cases were MSI and eight pathogenic germline mutations in hMSH2 or hMLH1 were detected in these two groups (53%). All the 17 early-onset sporadic cases were MSS and no germline mutations were detected among the seven investigated cases. Thirteen out of 15 (81%) familial cases were MSI and p53 protein-negative, whereas 13/14 (93%) sporadic cases were MSS and strongly p53 protein-positive. This extensive molecular investigation shows that simple tests such as MS study combined with hMSH2 and hMLH1 protein immunostaining performed on tumoural tissues may provide valuable information to distinguish between familial, and probably hereditary, and sporadic CRC cases. © 2000 Cancer Research Campaig

Selective Epitaxial Growth Followed by in Situ Deposition of a- or Poly-Si for Seeded Soi.

AbstractSelective Epitaxial Growth (SEG) techniques find a growing number of applications in the field of Si IC's, such as, lateral isolation, vertical interconnects, seeded recrystallisation etc. In the present work, the use of Si SEG by CVD combined with in-situ deposition of a- or poly-Si for the improvement of SOI obtained by Zone Melting Recrystallisation (ZMR) or by Lateral Solid Phase Epitaxy (SPE) is described. The principle application for which the present work is intended is Three Dimentional (3D) Integration. One of the main constraints imposed on process is thermal compatibility with previously executed process steps. Hence the need to reduce the thermal budget for the Selective Epitaxial Growth as much as possible.</jats:p

Lithographie par faisceaux d'ions : simulations et résultats expérimentaux

Cet article décrit une nouvelle technique de lithographie qui utilise des faisceaux d'ions. Les avantages de cette technique sont discutés, et comparés à ceux présentés par d'autres méthodes lithographiques couramment utilisées. La résolution de la lithographie ionique est étudiée expérimentalement par irradiation de résine PMMA à l'aide d'ions légers (H+) et d'ions lourds (Ga+). Des motifs géométriques de dimensions inférieures à 100 nm ont été transférés dans la résine (PMMA) à partir de masques adaptés (membranes minces à trous). L'effet, sur la résolution, des atomes de recul créés pendant l'irradiation est mis en évidence à l'aide d'un programme de simulation du freinage des ions dans la matière amorphe. Des profils de développement de la résine après irradiation aux ions Ga+ sont simulés sur ordinateur. L'utilisation, pour la lithographie, de machines ioniques à sources d'ions à métaux liquides est discutée