VARIOUS methods have from time to tinic been introduced for thc rapid microscopical esamination of new growths and inflammatory tissues removed a t operation, but on the whole the results have not been satisfactory, owing to the imperfect preparations obtained in the short spacc of time allowcd. Thc latc Professor S. G. Shattock, to whom English surgeons of experience rcferred for a final opinion on the microscopical examination of new growths, was strongly opposed to methods of rapid diagnosis, owing to errors dependent upon the technique and the short time available for microscopical examination. Dr. E. H. Shawl, howcver, has done much work on the perfccting of a method for the rapid diagnosis of ncw growths, and in his hands the results obtained have 1m.n Very successful.It occurred to us that as perfect preparations of intestinal parasites are obtained when films of intestinal mucus or fzeces arc fixed in the wet in Schaudinn's fluid, it might be possible to cmploy this method for the examination of new growths. Dudgeon and Jewesburyz used Schaudinn's solution for the cytological cxamination of human milk, and as a result obtained beautiful preparations of the various cells. In our hands wet films of new growths and inflammatory tissues removed a t operation have given a rapid and easily workable tcchnical method. The results of the first 200 consecutive specimens studied by this method, upon which this paper is based, have been very successful, as judged by the control examination of sections of the same tissue prepared in paraffin by the usual technique.Experience is required for this rapid method, as for all othcr laboratory methods, and it is essential to possess a sound knowledge of the microscopical study of new growths and inflammatory tissues by the usual technique. We consider that the advantages of the method arc the beautiful preparation of individual cells and fragments of tissue which are seen in the films, the simplicity of the technique, and the small amount of material required for the preparation of thc films ; all the necessary apparatus, with the exception of the microscope, can easily be carried in a portable casc 12 in. by 8 in. by 3 in. Mistakes have occurred, but they are few in number, and only 6 out of 200 cxaminations were definitely serious errors. It is possible that in course of time, and with greater knowledgc of this method, such mistakes will hc less

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Background: MET belongs to the semaphorin superfamily of signaling proteins, containing three protein families (semaphorins, plexins, MET and RON) that have central roles in cell signaling. The MET receptor tyrosine kinase is involved in regulating cell growth/proliferation, survival, angiogenesis, cell scattering, cell motility and migration. Mutations in MET have been identified in various human cancers including lung cancer and papillary renal cell carcinomas. MET mutations occur within the extracellular seven-blade β-propeller fold sema domain (E168D, L229F, S325G, N375S), the juxtamembrane domain (R988C, T1010I), and the kinase domain (M1268T). We hypothesized that these mutations would have differential effects on the kinase inhibition. Methods: We modeled the various MET mutations from different functional domains of the receptor using Cos-7 transfection cell system to determine their effect on MET signaling and sensitivity to a selective MET kinase inhibitor SU11274. Sensitivity to SU11274 inhibition was assayed by phospho-immunoblotting using phospho-specific antibody against the major tyrosine kinase phosphorylation epitopes pY1234/1235 of the MET kinase in vitro. Results: First, we identified that mutations in the sema and juxtamembrane domain were activating as defined by ligand-independent constitutive receptor activation. SU11274 was capable of inhibiting ligand induced signaling through the wild-type MET as well as mutant MET receptors harboring mutations in the sema, juxtamembrane and tyrosine kinase domain. However, SU11274 inhibition of mutant MET was mutation-dependent, with the juxtamembrane domain mutations R988C and T1010I resulting in a receptor form that was less sensitive to SU11274. Mutations in the sema and kinase domain also resulted in varying sensitivity to inhibition by SU11274 inhibition. Interestingly, the kinase domain L1243R mutation in MET (homologous to the epidermal growth factor receptor L858R-EGFR sensitizing mutation in lung cancer) substantially sensitized the mutant MET receptor to SU11274 inhibition with complete p-MET inhibition at 0.5 μM compared to 5 μM as in wild type. On the other hand, the activating M1268T mutation in the kinase domain was less sensitive to SU11274 than the wild type receptor. Conclusion: Mutations in the sema and juxtamembrane domain of MET result in receptor activation. The small molecule inhibitor SU11274 is active against wild type and various mutated MET receptor. Further studies to characterize the signaling effects and the mechanism of sensitivity and resistance of MET mutations to specific inhibitors are crucial in the successful development of therapeutic MET inhibitors in personalized cancer therapy.