Layered expression scanning: rapid molecular profiling of tumor samples.

Layered expression scanning is a new approach to comprehensive molecular analysis of tumor samples that uses a layered array of capture membranes coupled to antibodies or DNA sequences to perform multiplex protein or mRNA analysis. Cell or tissue samples are transferred through a series of individual capture layers, each linked to a separate antibody or DNA sequence. As the biomolecules traverse the membrane set, each targeted protein or mRNA is specifically captured by the layer containing its antibody or cDNA sequence. The two-dimensional relationship of the cell populations is maintained during the transfer process, thereby producing a molecular profile of each cell type present. Reduction-to-practice of the technique is demonstrated by analysis of prostate-specific antigen (PSA) protein, gelatinase A protein, and POV1 (PB39) cDNA. As layered expression scanning technology progresses, we envision a laboratory method that will have multiple applications for high-throughput molecular profiling of normal and tumor samples.

MEN1 gene mutation analysis of high-grade neuroendocrine lung carcinoma.

Neuroendocrine tumors of the lung consist of a spectrum of neoplasms, including typical carcinoids, atypical carcinoids, large-cell neuroendocrine carcinomas (LCNEC), and small-cell lung carcinomas (SCLC). We previously reported frequent inactivation of the gene responsible for multiple endocrine neoplasia type 1 (MEN1) in both typical and atypical carcinoid tumors. In the present study, we extend the analysis of human NE lung tumors to include 9 primary SCLCs, 36 SCLC cell lines, and 13 primary LCNECs for MEN1 gene inactivation. In SCLC, loss of heterozygosity (LOH) at the MEN1 gene on chromosome band 11q13 was detected in one primary tumor and two cell lines. The coding sequence and splice junctions of the MEN1 gene were screened for mutations in all 44 tumors and cell lines, and no mutations were detected. Northern blot analysis of 13 SCLC cell lines showed the MEN1 transcript to be present and of normal size. In LCNECs, a somatic frameshift in the MEN1 gene (1226delC) was found in one of 13 tumors, representing the first mutation observed outside the spectrum of neoplasms associated with MEN1. Interestingly, neither a deletion nor a mutation was detected in the other allele, and wild-type mRNA sequence was expressed in the tumor, suggesting that the MEN1 gene was not inactivated by a conventional two-hit mechanism. The data support the hypothesis that SCLC and lung carcinoids develop via distinct molecular pathways; however, further investigation is necessary to determine the significance of the MEN1 gene mutation observed in a single case of LCNEC. Published 2000 Wiley-Liss, Inc.