Abstract. The genomic region containing PIK3CA was found to be amplified in esophageal squamous cell carcinoma (ESCC) tissue. PIK3CA at 3q26, which encodes the p110· catalytic subunit of phosphatidylinositol (PI) 3-kinase, is a unique intracellular signal transducer characterized by its lipid substrate specificity. In order to characterize PIK3CA in ESCC, we investigated hot-spot mutations in exons 1, 9 and 20, the copy number gain, the expression levels of mRNA and protein. Analysis in exon 9 of the PIK3CA gene revealed mutation in 7.7% (4 of 52) of ESCC samples. No mutation was detected in either exon 1 or exon 20. Copy number amplifications of PIK3CA were found in 12 of the 45 patients (26.7%). PIK3CA mRNAs were examined in 37 ESCC patients as determined by quantitative RT-PCR and the mean mRNA level of PIK3CA in ESCC tissues was 2.61-fold higher compared with that in corresponding non-tumorous esophageal epithelia (P<0.001). Immunohistochemically, positive immunoreaction for PIK3CA was detectable in 33 of 66 (50.0%) ESCC cases, while it was not detectable in the remaining 33 cases. Furthermore, comparing the cases with negative staining with those with positive staining for PIK3CA, the presence of node metastasis was significantly correlated with those with positive staining (P<0.05). This study is the first report providing comprehensive analysis of PIK3CA expression in ESCC. These results indicate that PIK3CA may play a crucial role in the development of ESCC and serve as an indicator for lymph node metastasis.

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A novel ␣-tricalcium phosphate (TCP) and gelatin gel composite cement was prepared, and the effects of gelatin content, liquid/powder ratio, setting time, and additives (rod-like hydroxyapatite and CaTiO 3 particles) on the microstructure and compressive strength of the setting product were investigated. Addition of gelatin gel to ␣-TCP cement resulted in the formation of a porous solid possessing pores of 20-100 m in diameter whose pore diameter increased with increasing gelatin gel content. The compressive strength of ␣-TCP cement after 1 week increased from 9.0 to 14.1 MPa with increasing gelatin gel content up to 5 wt % and thereafter decreased. The compressive strength of the cement containing 5 wt % gelatin gel increased with time up to 35 MPa after 1 month whereas without gelatin gel it was ∼20 MPa. Dispersion of 5 wt % of rod-like hydroxyapatite and CaTiO 3 powders with ␣-TCP cement containing 5 wt % gelatin gel increased the compressive strength after 1 week from 14.1 to 31.3 and 34.8 MPa, respectively.

Oral carcinogenesis is a complex process involving multiple genes. However, the genetic changes involved in this process are not apparent in identical oral squamous cell carcinomas (OSCCs). According to pathological characteristics, samples of normal tissue, oral dysplastic lesions (ODLs), and invasive cancers were obtained from identical OSCCs using laser microdissection (LMD). Large‐scale gene expression profiling was carried out on 33 samples derived from 11 OSCCs. We analyzed genes differentially expressed in normal tissues vs. ODLs and in ODLs vs. invasive tumors and identified 15 candidate genes with continuously increasing or decreasing expression during oral carcinogenesis. One of these genes, ISG15, was chosen for further characterization. Real‐time quantitative reverse transcription‐polymerase chain reaction and immunohistochemical analysis confirmed that ISG15 expression consistently increased during oral tumorigenesis. An ISG15 high‐expression level was significantly associated with poor prognosis (p = 0.027). In addition, patients with high‐expression tumors had a poorer 5‐year survival rate than patients with low expression levels (p = 0.019). In conclusion, we identified 15 genes with continuously increasing or decreasing expression during oral carcinogenesis. One of these, ISG15, is likely to be associated with both dysgenesis and tumorigenesis and may be a potential prognostic marker for oral cancer.

Background Anaplastic lymphoma kinase (ALK) fusion genes are found in 3%–5% of non‐small cell lung cancers (NSCLCs). ALK inhibitors show a very high response rate to ALK‐positive NSCLCs. However, the emergence of acquired resistance is inevitable. In this study, we investigated the drugs for overcoming resistance especially compound mutations after sequential treatment with crizotinib, alectinib, and lorlatinib. Method Next‐generation sequencing (NGS) and Sanger sequencing were performed on a liver biopsy tissue obtained from a clinical case. Ba/F3 cells in which mutant EML4‐ALK were overexpressed were prepared, and cell viability assay and immunoblotting were performed to check the sensitivity of five independent ALK inhibitors. Results I1171S + G1269A double mutation was identified by NGS and Sanger sequencing on a liver biopsy tissue from a patient who relapsed on lorlatinib treatment. Ceritinib and brigatinib—but not other ALK inhibitors—were active against the compound mutations in the cell line model. Conclusions With the sequential ALK inhibitors treatment, cancer cells accumulate new mutations in addition to mutations acquired previously. The identified compound mutation (I1171S + G1269A) was found to be sensitive to ceritinib and brigatinib, and indeed the patient's tumor partially responded to ceritinib. Key points ALK compound mutation was found in a clinical sample that was resistant to lorlatinib after sequential ALK‐tyrosine kinase inhibitor (TKI) treatment. Ceritinib and brigatinib are potential overcoming drugs against ALK I1171S + G1269A double mutation.