APC gene mutations play an important role in the initiation step of colorectal carcinogenesis in both familial adenomatous polyposis (FAP) patients and non-FAP patients. Although the APC gene is expressed in most tissues, including the lung, liver, kidney, and mammary gland, its somatic mutations have rarely been found in primary tumors affecting these organs. We have developed a sensitive yeast-based assay for screening almost the entire coding region of the APC gene. By this method, we have been able to detect somatic mutations of the APC gene in 57% of colorectal cancers and none in non-small cell lung cancers. Interestingly, the assay detected somatic APC gene mutations in 18% of breast cancers, in which APC gene mutation was previously considered rare. In the breast cancers, most of the APC mutations were distributed outside the mutation cluster region that has been advocated for colorectal cancers. We also noted a difference in the mutation pattern of the APC between colorectal and breast cancers. In colorectal cancers, all base substitutions were observed at C residues (5 of 5), whereas in breast cancers the majority of them were found at G residues (4 of 5). Furthermore, APC mutations were observed at a significantly high frequency in advanced stages of primary breast cancers (TNM classification, P < 0.05; T category, P < 0.01). Our data suggest that the etiology of the APC mutations and their biological role in carcinogenesis may differ between colorectal and breast cancers.

Here we report for the first time highly flexible quantum dot light-emitting diodes (QLEDs), in which a layer of red-emitting colloidal silicon quantum dots (SiQDs) works as the optically active component, by replacing a rigid glass substrate with a thin sheet of polyethylene terephthalate (PET). The enhanced optical performance for electroluminescence (EL) at room temperature in air is achieved by taking advantage of the inverted device structure. Our QLEDs do not exhibit parasitic EL emissions from the neighboring compositional layers or surface states of QDs over a wide range of driving voltages and do not exhibit a shift in the EL peak position as the operational voltage increases. Compared to the previous Si-QLEDs with a conventional device structure, our QLED has a longer device operational lifetime and a long-lived EQE value. The currently obtained brightness (∼5000 cd/m), the 3.1% external quantum efficiency (EQE), and a turn-on voltage as low as 3.5 V are sufficiently high to encourage further developments of Si-QLEDs.

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Hepatectomy for liver metastases from colorectal cancer has recently received general acceptance as a safe, potentially curative treatment. Most patients, however, die of recurrent disease after hepatectomy. The predictive factors for recurrence after first resection of liver metastases have not yet been clarified. The authors aimed to determine the factors that can predict recurrence, especially hepatic-only recurrence after hepatectomy for colorectal liver metastases. Seventy-six patients who underwent liver resection of colorectal metastases were studied retrospectively. Forty-seven (61.8%) of the patients had a recurrence. The patients' disease-free survival after first hepatectomy and the second recurrence sites were univariately and multivariately analyzed using 16 clinicopathologic variables. Wall invasion, lymph node metastases, lymphatic invasion, venous invasion of the primary tumor, 24 months or longer disease-free interval after resection of the primary colorectal cancer, and bilateral liver metastases significantly influenced the disease-free survival (log-rank test: p < 0.05). The multivariate analysis revealed that venous invasion of the primary tumor and bilateral hepatic metastases were independent risk factors for recurrence after hepatectomy. The liver was the only site of second recurrence in 23 patients. Patients with lymph node metastases and venous invasion of the primary tumor had a significant difference between hepatic-only and extrahepatic recurrence after first hepatectomy (chi-square test or Fishers' exact test: p< 0.05). Recurrence after hepatectomy was influenced more by factors associated with the primary colorectal cancer than factors surrounding the first liver metastases. Venous invasion of the primary colorectal cancer was the most important predictable factor for hepatic-only second recurrence.