Genome research using appropriately collected pathological tissue samples is expected to yield breakthroughs in the development of biomarkers and identification of therapeutic targets for diseases such as cancers. In this connection, the Japanese Society of Pathology (JSP) has developed “The JSP Guidelines on the Handling of Pathological Tissue Samples for Genomic Research” based on an abundance of data from empirical analyses of tissue samples collected and stored under various conditions. Tissue samples should be collected from appropriate sites within surgically resected specimens, without disturbing the features on which pathological diagnosis is based, while avoiding bleeding or necrotic foci. They should be collected as soon as possible after resection: at the latest within about 3 h of storage at 4°C. Preferably, snap‐frozen samples should be stored in liquid nitrogen (about −180°C) until use. When intending to use genomic DNA extracted from formalin‐fixed paraffin‐embedded tissue, 10% neutral buffered formalin should be used. Insufficient fixation and overfixation must both be avoided. We hope that pathologists, clinicians, clinical laboratory technicians and biobank operators will come to master the handling of pathological tissue samples based on the standard operating procedures in these Guidelines to yield results that will assist in the realization of genomic medicine.

Several simplified fixation methods were examined to determine their suitability for both molecular biological analyses and morphological study. Fixation with 10% v/v formalin alone at 4 degrees C and containing 5 mmol/L ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) at room temperature preserved significantly more high-molecular-weight DNA than 10% v/v formalin fixation at room temperature. The morphological differences between tissues fixed using these modified formalin fixation methods and conventional 10% v/v formalin fixation were negligible. Of the dehydration fixatives tested, 100% methanol did not cause regional differences due to artificial tissue shrinkage and the morphology of sections prepared by methanol fixation was preserved consistently better than that of acetone- or ethanol-fixed sections. All three dehydration fixatives preserved relatively higher-molecular-weight DNA and RNA, compared with formalin. Cold formalin, formalin containing EDTA at room temperature and 100% methanol are recommended as standard and additional fixatives routine clinicopathological laboratory use.

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The ability to resist anoikis is critical for carcinoma cells to metastasize. Although several lung adenocarcinoma cell lines were shown to repress anoikis through the activation of Src, it remains unknown whether Src actually plays a crucial role in anoikis resistance in lung adenocarcinoma tissues. We examined 20 human lung adenocarcinoma tissues with lymphatic permeation and nine cell lines to investigate whether intralymphatic floating carcinoma cells in the tissues, used as an in vivo model of anoikis resistance, actually suppressed anoikis and whether cell lines in suspension culture, an in vitro model of anoikis resistance, survived through Src activation. We observed that the intralymphatic carcinoma cells aggregated tightly to form nests expressing E-cadherin and phosphorylated Src (p-Src). The apoptotic indices of these cells were comparable to those of extracellular matrix adhesive cells in all tissues, indicating that the intralymphatic cells actually evaded anoikis. Next, we found that the nine cell lines in suspension aggregated loosely (five cell lines) or tightly (four cell lines), and all cells resisted anoikis. Upon detachment, four cell lines (LC-KJ, HCC827, H1650, and H1975) formed compact spheroids that expressed E-cadherin and p-Src. The spheroids were similar to intralymphatic tumour nests and were thus considered to be a suitable model of the nests. The spheroids of the four cell lines underwent apoptosis after treatment with the Src/Abl/Kit inhibitor PP1 or Src/Abl inhibitor bosutinib. On the other hand, the Abl/Kit inhibitor imatinib did not affect cell growth or apoptosis in the four types of spheroids. These results indicate that Src, but not Abl or Kit, plays an essential role in the development of anoikis resistance in lung adenocarcinomas.

Directional migration of primordial germ cells (PGCs) toward future gonads is a common feature in many animals. In zebrafish, mouse and chicken, SDF-1/CXCR4 chemokine signaling has been shown to have an important role in PGC migration. In Xenopus, SDF-1 is expressed in several regions in embryos including dorsal mesoderm, the target region that PGCs migrate to. CXCR4 is known to be expressed in PGCs. This relationship is consistent with that of more well-known animals. Here, we present experiments that examine whether chemokine signaling is involved in PGC migration of Xenopus. We investigate: (1) Whether injection of antisense morpholino oligos (MOs) for CXCR4 mRNA into vegetal blastomere containing the germ plasm or the precursor of PGCs disturbs the migration of PGCs? (2) Whether injection of exogenous CXCR4 mRNA together with MOs can restore the knockdown phenotype? (3) Whether the migratory behavior of PGCs is disturbed by the specific expression of mutant CXCR4 mRNA or SDF-1 mRNA in PGCs? We find that the knockdown of CXCR4 or the expression of mutant CXCR4 in PGCs leads to a decrease in the PGC number of the genital ridges, and that the ectopic expression of SDF-1 in PGCs leads to a decrease in the PGC number of the genital ridges and an increase in the ectopic PGC number. These results suggest that SDF-1/CXCR4 chemokine signaling is involved in the migration and survival or in the differentiation of PGCs in Xenopus.