Novel microdeletion in the transforming growth factor beta type II receptor gene is associated with giant and large cell variants of nonsmall cell lung carcinoma.

Mutations in the tumor suppressor gene transforming growth factor beta (TGFB) Type II receptor (TGFBR2) are frequently found in many cancers with microsatellite instability, but are less common in lung cancer. In the present study, we looked for mutations in TGFBR2 in nonsmall cell lung carcinoma (NSCLC) cells and tissues. A novel homozygous microdeletion (c.492_507del) was identified in two cell lines derived from the same giant cell carcinoma (GCC) and was confirmed in the corresponding tumor tissues. Furthermore, a heterozygous c.492_507del was found in the germ-line of one patient, as well as in the other GCC cases and some large cell carcinomas (LCC) but not in other subtypes of NSCLC. The 16 bp-microdeletion introduced a premature stop codon at positions 590-592 of the cDNA, resulting in a truncated TGFBR2 protein with a mutated transmembrane domain and loss of kinase domain. The GCC cells were characterized as being unresponsive to TGFB induction both in growth inhibition and stimulation of extracellular matrix protein. Moreover, after the reconstitution of wild-type TGFBR2 expression, the sensitivity to TGFB was restored. Therefore, mutated TGFBR2 seems to play an important role in the abrogation of TGFB signal transduction in GCC cells.

[Differentially expressed genes between a fertile patient and an infertile patient in a large Chinese androgen insensitivity syndrome pedigree].

OBJECTIVE: To screen and identify differentially expressed genes between a fertile patient and another infertile patient who belonged to a large Chinese pedigree affected with androgen insensitivity syndrome (AIS). METHODS: We constructed the forward and reversed subtracted libraries using genital skin fibroblasts (GSF), which were obtained from the fertile patient MJ and infertile patient ZGJ, as tester respectively. Candidate clones were screened with colony in situ hybridization, dot blot, and Southern blot analysis step by step and conformed with Northern blot analysis. The potential positive clones were sequenced and the homology of the sequences was analyzed. RESULTS: The forward and reversed subtracted libraries containing differentially expressed pattern of two GSF cell lines were constructed. Two positive clones identified by Northern blot were obtained in the reversed subtracted library. Eleven candidate clones from the two libraries that failed to hybridize with both RNA populations were obtained simultaneously, which might represent differentially expressed low abundance transcripts. Sequencing results and homology analysis demonstrated that the two positive clones were significantly homologous with the genes of autotaxin-t and calcium binding protein calcyclin (S100A6), respectively. CONCLUSIONS: Two positive clones and eleven clones showing no hybridization signals may represent differentially expressed genes between the two GSFs. This finding may be useful to elucidate the molecular mechanisms leading to phenotypic variation and preserved fertility of the AIS pedigree.