Detection of p53 gene mutation by using a novel biosensor based on localized surface plasmon resonance.

Few studies to date have reported on the development and application of a nanobiosensor based on localized surface plasmon resonance (LSPR) for detecting gene mutations. This study aimed to develop a novel LSPR biosensor used for detecting p53 mutation. Nanosphere lithography was used to fabricate the silver nanoparticles. The DNA probe was designed to recognize the target sequence and immobilized on the chip surface by a covalent-coupling method using amine-group ligands. Synthetic oligonucleotides or PCR products were amplified from genomic DNA taken from blood samples and hybridized with the immobilized probe. Wild-type and mutant p53 was detected by measuring shifts in peak of LSPR extinction spectra. The low detection limit of the sensor for target sequence was 10 nM, and detection occurred over a wide dynamic range (10 nM - 10 µM). Importantly, the differences in measuring signal between wild-type and mismatched p53 DNA was significant, allowing for this sensor to effectively discriminate against single base mutations. In conclusion, we developed a biosensor with potential as a rapid, label-free, sensitive, and low-cost method for detecting p53 mutation. Our results suggest that such an LSPR-based biosensor provides an attractive alternative for clinical detection of genetic mutation.

Variation of human papillomavirus 16 in cervical and lung cancers in Sichuan, China.

Although the crucial role of human papillomaviruses (HPVs), especially HPV-16 in various cancers has been confirmed, the variation of HPV-16 among different cancers have not been investigated in a specific geographic location. In order to elucidate whether similar HPV-16 variants are involved in different kinds of cancers in the same geographic location, the analysis of sequence variants of E6 and E7 oncogenes and L1 gene of HPV-16 in cervical and lung cancers in Sichuan, China, was carried out. Tissue samples from 122 cervical cancers, 104 lung cancers, and 138 controls were subjected to RT-PCR or PCR, sequencing, and sequence analysis. The infection rates of HPV-16 in cervical, lung cancers, and non-malignant controls were 68.9%, 17.3%, and 37.0%, respectively. Asian prototype variants prevailed in cervical and lung cancers, while European prototype variants in non-malignant controls. In comparison to the lung cancer, cervical cancer showed a much higher diversity of HPV-16 oncogenes. These results indicate that in Sichuan, China, Asian prototype variants of HPV-16 are more pathogenic than their European counterparts.

[The values of urine cysteine protein activity in the diagnosis of ovarian cancer].

The levels of urine cysteine protease (UCP) were detected in the urines of 70 gynecological cancers, 50 gynecological benign tumors and 50 normal women. The values of UCP assay of gynecological cancers were much higher than those of benign and normal samples (P < 0.01). Best cut off point for diagnosis of gynecological cancers was P95 and UCP cut off value was 0.24 pmol.min-1/L by using percentile and ROC curve. The sensitivity of UCP assay was 90%, specificity 80% and accuracy 86%. The sensitivity for ovarian cancers was 95%, but 77% and 85% for corpus and cervical cancers respectively. There were no differences between UCP and CA125 (sensitivity 85%, specificity 87%, accuracy 84%) in the diagnosis of ovarian cancers. In 7 cases of 8 cases of stage I ovarian cancers, UCP were abnormal. In 6 cases of the same group, CA125 were normal (< 35,000 U/L). So UCP may be better than CA125 in the diagnosis of early ovarian cancer. The sensitivity of lactate dehydrogenase (LDH) isoenzyme was 75% in ovarian cancer which was lower than UCP and CA125, but the specificity 85%. LDH isoenzyme still was one of important tumor markers for diagnosis. Combined assays with UCP, CA125 and LDH isoenzyme may reach the sensitivity 96% and specificity 100% evidently. These data implied that UCP may be a good tumor marker in gynecological cancers especially for ovarian cancers in future.