Short-duration light pulses have been observed to be emitted at the moment of microfracture (pit size of 10-20 µm) when two solids are rubbed against each other. When a fused silica sample is scratched by a diamond grain, the observed light pulses have a rise time of less than 10 ns and pulse width of 10-20 ns. A continuous spectrum at 500-800 nm is observed, suggesting 3000° C material part. At 300-400 nm, intense line spectra are observed, which suggests the existence of gaseous *O2 molecules desorbed from SiO2. When the solid fractures, the fractured part heats up to a very high temperature almost instantaneously, and cools down within 10-20 ns.

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Primary culture of cancer cells derived from each patient’s tumor can provide important information of the “individual tumor.” It is general to use cell lines in basic research filed. However, cell lines are quite different from clinical cancers. Clinical cancer tissues are composed of not only cancer cells but also tumor microenvironments such as stromal cells and tumor vessels. The primary culture method of clinical cancer with tumor niche microenvironments has not been optimized. We have developed a simple 2D-culture method for primary colorectal cancer (CRC). We obtained 30 samples from surgically resected tumor. They were mechanically and enzymatically digested and fibrotic tissue and bacteria were excluded using customized two size filters. And we cultured the obtained cells on a matrigel-coated plate with embryonic stem (ES) cells culture medium. We named these cultured cancer cells, “isolated-tumor derived Cancer Cells (iCCs).” All iCCs grew and about 80 % of iCCs were successfully passaged. Twenty-three iCCs were transplanted into the subcutaneous layer of NOD-SCID mice, and the tumor growth and histology of iCCs were examined. The morphology was similar to each parental clinical tumor. And microarray analysis showed that RNA expression of iCCs was similar to each parental tumor. Furthermore, we examined the culture medium; our modified ES culture medium (ES-cultured iCCs) and 10% FBS medium (serum-cultured iCCs). The expression of surface markers regarding cancer stem cells such as CD44 and CD24 were different between ES-cultured iCCs and serum-cultured iCCs, and drug sensitivity of iCCs were also different. FACS analysis and immunocytochemistry revealed that iCCs contained PDGFR-positive cells. The results of multi-drug sensitivity assay were different between iCCs and cell lines especially in PDGFR inhibitor. Strong correlations were observed between the results of multi-drug sensitivity assay of iCCs and clinical outcomes of chemotherapy. We report an innovative primary culture method and the in vivo and in vitro analyses of iCCs, leading to the future application. Citation Format: Shiki Fujino, Norikatsu Miyoshi, Masayuki Ohue, Yusuke Takayashi, Masayoshi Yasui, Hidekazu Takahashi, Naoyuki Haraguchi, Jhunichi Nishimura, Taishi Hata, Tsunekazu Mizushima, Yuichiro Doki, Masaki Mori. Niche microenvironments essential for tumor heterogeneity of primary cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2930. doi:10.1158/1538-7445.AM2017-2930