Comparison of the Digene HC2 assay and the Roche AMPLICOR human papillomavirus (HPV) test for detection of high-risk HPV genotypes in cervical samples.

Many different methods with different sensitivity and specificity have been proposed to detect the presence of high-risk human papillomavirus (HR HPV) in cervical samples. The HC2 is one of the most widely used. Recently, a new standardized PCR-based method, the AMPLICOR HPV test, has been introduced. Both assays recognize the same 13 HR HPV genotypes. The performances of these two commercially available assays were compared in 167 consecutive women (for a total of 168 samples) who presented at the Colposcopy Clinic either for a follow-up or for a diagnostic visit. Concordant results were found in 140/168 cervical samples (overall agreement, 83%; Cohen's kappa = 0.63). Twenty-eight samples gave discordant results: 20 were positive with the AMPLICOR HPV test and negative with the HC2 assay, and 8 were negative with the AMPLICOR HPV test and positive with the HC2 assay. The genotyping showed that no HR HPV was detected in the 8 HC2 assay-positive AMPLICOR HPV test-negative samples, while in 8/20 AMPLICOR HPV test-positive HC2 assay-negative samples, an HR HPV genotype was found. The AMPLICOR HPV test scored positive in a significantly higher percentage of subjects with normal Pap smears. All 7 cervical intraepithelial neoplasia grade 3 patients scored positive with the AMPLICOR HPV test, while 2 of them scored negative with HC2. Both tests had positive results in the only patient with squamous cell carcinoma. In conclusion, this study shows that the HC2 assay and the AMPLICOR HPV test give comparable results, with both being suitable for routine use. The differences noted in some cases may suggest a different optimal clinical use.

K-ras gene mutational analysis supports a monoclonal origin of biphasic pleomorphic carcinoma of the lung.

We investigated 27 pleomorphic carcinomas of the lung for exon 1 K-ras gene mutations using polymerase chain reaction-single-strand conformation polymophism analysis and direct sequencing. All pleomorphic carcinomas were biphasic, that is, composed of an adeno-, squamous- or large-cell-carcinomatous component associated with a spindle- and/or giant-cell component. Of 27 cases, six (22%) showed K-ras codon 12 mutations, which is a figure higher than that previously reported on in pure sarcoma-like pleomorphic carcinomas. Five tumors displayed the same mutation in both the epithelial and the sarcomatoid components, whereas in one tumor the mutation was restricted to the epithelial component. All mutations occurred in smokers, and were transversions, including GGT (glycine) to TGT (cysteine) change in two cases, to GCT (alanine) in two and to GTT (valine) in two. No significant relationships were found between the occurrence and type of mutations and patients' survival or any other clinicopathological variable, suggesting that K-ras mutations are early events in the development of these tumors. Our results indicate that most, though not all, biphasic pleomorphic carcinomas of the lung are monoclonal in origin, and that cigarette smoking may have a causative role in the development of K-ras alterations in these tumors, as all mutations are transversions.