Diagnosis of thyroid carcinoma by ultrasonic examination: comparison with diagnosis by fine needle aspiration cytology

Ultrasonic examination was performed on 120 patients who later underwent surgery. Ultrasonically, among the 64 cases of benign nodules and the 56 of carcinomas, 50 and 46 cases respectively were diagnosed correctly. In making the ultrasonic diagnosis, the following findings were considered; shape, margin, boundary, internal echoes, hyperechoic spots, the echo level of the nodule and the cystic pattern. The sensitivity for carcinoma diagnosis was 0.82, specificity was 0.78 and accuracy was 0.80. The diagnostic accuracy for the same patients using a newly devised diagnostic system that utilized a fuzzy inference was almost as high as that of the conventional method. Furthermore, the diagnostic accuracy of both of these methods did not differ significantly from that obtained by fine needle aspiration cytology. Therefore, non invasive ultrasonic examination is considered to be very useful for the detection and diagnosis of thyroid carcinoma.

Correlation between tumorigenicity and expression levels or splicing patterns of transcripts of the human papillomavirus type 16 E6 gene

For determination of the correlation between tumorigenicity and the expression levels or splicing patterns of E6 mRNAs of the human papillomavirus type 16 in established cells, a vector containing the intact E6 open reading frame which expresses both unspliced and spliced mRNAs, one expressing only unspliced E6 mRNA, and one expressing both unspliced and spliced mRNAs but producing only truncated E6 proteins were constructed. In transformation assays and analyses of E6 mRNAs, a higher expression level of unspliced E6 mRNA was found to be closely associated with tumorigenicity. Furthermore, it was also related with anchorage-independent growth and a decreased serum requirement of the cells.

Surgical strategy for papillary carcinoma of the thyroid in an iodine rich area: decision on the operation table

In iodine rich areas the incidence of papillary carcinoma of the thyroid is extremely high but its prognosis is favorable. When papillary carcinoma is confined to one lobe, our standard surgical procedure has been total lobectomy with isthmusectomy rather than total thyroidectomy. Our followup study of 185 such patients reveals considerable difference in the outcome between the 85 patients with gross thyroid capsular invasion and the 100 patients without, regardless of the presence of cervical lymph node metastasis. In the latter group, the tumor could be completely resected in all patients; although 4 cases had recurrence and required reoperation, 3 patients are alive and well and one died of other disease. In contrast, 20 patients in the former group had incomplete resection of the tumor, 4 patients developed recurrence and needed to be reoperated and 7 patients eventually died of thyroid cancer. One hundred thirty three patients (71.9%) underwent modified neck dissection at the time of surgery to find lymph node metastasis in 37 of 59 cases (62.7%) without gross thyroid capsular invasion and 64 of 74 cases (86.5%) with such invasion. The difference is statistically significant (P < 0.05). From these results we conclude that for papillary thyroid cancer in iodine rich areas total lobectomy with isthmusectomy is the treatment of choice when gross thyroid capsular invasion is not recognized on the operation table. However, when gross thyroid capsular invasion is recognized, total or near total thyroidectomy has to be performed.

Comparative study on E6 and E7 genes of some cutaneous and genital papillomaviruses of human origin for their ability to transform 3Y1 cells

E6 (or E7) genes of some genital and cutaneous human papillomaviruses (HPVs) were compared for their ability to transform cells of a rat fibroblastic line (3Y1) by using recombinant retroviruses. The E6 gene of genital cancer-associated HPV 16 or 18 was found to induce a characteristic morphological change, i.e., densely packed arrays of elongated cells forming swirl patterns. This change is the same as that induced by the E6 gene of cutaneous cancer-associated HPV 5, 8, or 47, which we described previously. The E6 gene of HPV 1 or 11, associated with benign tumor of cutaneous or genital tissue, respectively, induced no such change. The E6 genes of all these cutaneous and genital HPVs enhanced anchorage-independent growth of the target cells induced by E7 gene of HPV 16 or 18, and this enhancing activity of HPVs 16, 18, and 47 was stronger than that of HPVs 1 and 11. A distinct type of morphological transformation of 3Y1 cells, i.e., rounded miniaturized cells that were densely packed without forming any distinctive arrays, was found to be induced strongly by E7 genes of HPVs 16 and 18, weakly by E7 of HPVs 1 and 11, and not at all by E7 of HPV 47. The results suggest that the intensity of the morphological change induced by E6 genes, rather than E7 genes, is correlated to the risk of malignant conversion of the lesion with which the corresponding HPVs are associated.

Differences in transforming activity and coded amino acid sequence among E6 genes of several papillomaviruses associated with epidermodysplasia verruciformis

Using the polymerase chain reaction technique, we cloned and sequenced DNA fragments containing the E6 genes of the epidermodysplasia verruciformis (EV)-associated HPVs 5, 8, 14, 20, 21, 25, and 47, of which only the sequences of HPVs 5, 8, and 47 have previously been reported. Based on the deduced amino acid sequence homology (57.3 to 83.0%), these HPVs could be divided into two clusters: HPVs 5, 8, and 47, and HPVs 14, 20, 21, and 25. The E6 genes of three HPVs from each cluster were examined for transforming activity toward a cultured rat fibroblast cell line, 3Y1, using the retrovirus-mediated gene transfer technique, and all were found to induce morphological transformation. However, the E6 genes of the first cluster were more potent than those of the second. Since HPVs 5 and 8 are the most frequently found HPVs in malignant lesions of EV patients, the observed in vitro transforming activities of the E6 genes may reflect their oncogenic potential in humans.

Genome organization and taxonomic position of human papillomavirus type 47 inferred from its DNA sequence

The complete nucleotide sequence of human papillomavirus type 47 (HPV-47) DNA isolated from the lesion of epidermodysplasia verruciformis (EV) was determined. The computer-aided comparison of HPV-47 with other EV-associated viruses using the available sequence data on them revealed that HPV-47 resembles both HPV-5 and HPV-8 as much as HPV-5 and HPV-8 resemble each other, and it led us to regard these three viruses as one cluster and HPV-19 and HPV-25 as another. The conclusion implies that HPV-47 as well as HPV-5 and HPV-8 is associated with the cancer occurrence in EV. Two sets of splicing donor and acceptor sequences in HPV-47, which were previously shown to work in vivo, are also conserved in HPV-5 and HPV-8. One of them allows formation of an ORF predicted to encode an E1/E4 fused protein.

The primary structure of major viral RNA in a rat cell line transfected with type 47 human papillomavirus DNA and the transforming activity of its cDNA and E6 gene

A transformed cell line (RC335) showing higher saturation cell density was obtained from 3Y1 cells (a fibroblastic cell line of rat) transfected with DNA of human papillomavirus type 47 (HPV-47), an epidermodysplasia verruciformis-associated virus, which our laboratory reported previously. The cell line was found to produce a major and several minor species of viral RNAs. The primary structure of the major viral RNA in RC335 was extensively studied and found to consist of two exons and contain open reading frames (ORFs) E6, E7, and a fused ORF, E1/E4. The major RNA was indicated to play an important role in the transformation of RC335 by an experiment with the recombinant retrovirus designed to produce the RNA containing these ORFs, i.e., the recombinant virus induced transformation similar to that in RC335 upon infection of 3Y1 cells. Furthermore the experiments with recombinant viruses carrying a nonsense mutation or large deletion in the above ORF(s) indicated that E6 was necessary and sufficient for the transformation.