The RET gene is a responsible gene of multiple endocrine type 2（MEN 2）and familial medullary thyroid carcinoma（FMTC）, and the major clinical manifestation of this syndrome is a medullary thyroid carcinoma （MTC）. We have been performing RET gene diagnosis in our laboratory since 1994. Exons 10, 11, 13–16 in the RET gene have been analyzed by PCRbased DNA sequencing. Molecular diagnosis of the RET gene is indispensable in identifying MEN 2 and should be performed for all cases with MTC. However, it is difficult to maintain RET gene diagnosis for research level eternally. Therefore, RETgene diagnosis for an advanced technology to the Ministry of Health, Labour and Welfare was applied and was approved in August 2008. Until now, the RET gene diagnosis for advanced technology was done in 15 cases（11 probands and 4 relatives）. Of these, 3 probands and 4 relatives had RET gene mutation. Among them, 3 probands and 1 relative underwent total thyroidectomy after clinical screening of pheochromocytoma. We are currently accumulating the data to promote the advanced technology to the technology covered by the national health insurance.
All bilateral and 10–15 ％ of unilateral retinoblastomas are hereditary with a germline inactivating mutation of the RB1 gene. An early diagnosis increases a chance for eye and eyesight preservation. About half of newly diagnosed retinoblastoma cases in Japan visit National Cancer Center Hospital, in which 88probands and 74 relativeschose genetic tests from 1998 to March 2010. The tests typically consist of dHPLC（WAVE）analysis for the entire RB1 coding region followed by direct sequencing, direct sequencing of the RT-PCR products of all RB1 exons, Multiplex Ligation-dependent Probe Amplification （MLPA） and FISH. Pathogenic mutations were detected in 93 ％ for bilateral cases and unilateral cases with family history but 11 ％ for unilateral cases without family history. Because sensitivity is not sufficient for each single test, and detection of mosaicism and splicing aberration requires FISH and RT-PCR, respectively, the combination of multiple tests is necessary.
Cancer invasion and metastasis is initiated by the event that cancer cells are released from the primary cell aggregate. The epithelial-mesenchymal transition （EMT）is characterized by the loss of epithelial characteristics and the gain of mesenchymal attributes. During this transition, epithelial cells down-regulate cell-cell adhesion systems, lose their polarity, and acquire a mesenchymal phenotype associated with increased interaction with extracellular matrix（ECM） and enhanced migratory capacity. The EMT is considered to play a major role in the initial step of cancer invasion and metastasis. Furthermofe, it is also thought to be involved in pathological settings such as fibrotic disorders and neurofibroma formation. Therefore, suppression of EMT and mesenchymal phenotype can be a new therapeutic approach for those refractory diseases. We have recently developed a novel in vitro EMT induction system which is currently used for screen small molecular weight compounds inhibiting EMT.