BackgroundThe variation of human papillomavirus (HPV) genes or HPV variants demonstrates different risks of cervical cancer. Mutation in the long control region (LCR) at YY1-motifs is one of the mechanisms for enhancing viral oncogene expression during the course of cancer cell progression. In Thai women, cervical cancers are almost always associated with HPV16 variant sub-lineage Asian (HPV16As); however, the mechanism involved remains elusive. The aim of this study was to understand further the oncogenic potential of HPV16As.MethodsA total of 82 HPV16-positive specimens from Thai women were selected from formalin-fixed paraffin-embedded cervical tissues, and the full length E6 gene of each specimen was amplified and sequenced. LCRs of the HPV16As-positive cases were amplified and sequenced to analyze their polymorphisms. Transcriptional activities of the HPV16As LCRs were then compared with sub-lineage European (EUR), sub-lineage Asian-American 1 (AA1) and HPV16 prototype by insertion of the LCRs into the pGL3-Basic vector.ResultsThe HPV16 DNA sequences were classified as HPV16 prototype (18.3%), Asian (As, 61%), Asian American-1 (AA1, 8.5%), European (EUR, 7.3%), Asian African-2 (AFR2, 3.7%) and Java-135C (J135C, 1.2%). The prevalence of HPV16As was 30% in low-grade squamous intraepithelial lesion (LSIL), while that in high-grade squamous intraepithelial lesion (HSIL) and squamous cell cervical carcinoma (SCC) were 63.9% and 66.7%, respectively, which demonstrates a significant association of HPV16As with the disease severity. LCR polymorphisms from 43 HPV16As positive cases were analyzed by PCR-sequencing. Thirty-eight nucleotide variation positions spanned nucleotide positions 7157–82. Ten new mutations found in the HPV16As LCRs were located predominantly at the enhancer and proximal to the 3’-end of the early promoter. The LCRs of the common HPV16As, EUR and AA1 showed 5, 13 and 23-fold higher activity than the HPV16 prototype LCR, while those of the new nucleotide variations of As showed 19 (As-sv1) and 30 (As-sv14) -fold higher activity than the HPV16 prototype.ConclusionsHPV16As DNA sequence variation, especially at the proximal to early promoter in the LCR, enhances transcriptional activity. This could be one of the possible mechanisms for HPV16As-associated cervical cancer development.

The relevance of 8 contemporary classification and grading systems for ductal carcinoma in situ (DCIS) of the breast was examined in 100 tumors by comparing DCIS grade with grade of the concurrent infiltrating ductal carcinoma (IDC). Besides tumor size and nodal status, the immunohistochemical parameters in both lesions were compared, including estrogen receptor, progesterone receptor, c-erbB-2 protein, E-cadherin, vimentin, Ki-67 (MIB1), and p27. Nuclear grading of DCIS alone or in combination with architectural pattern and necrosis showed the best correlation with grade of the invasive component. There also was a positive correlation between every biologic marker expressed in DCIS and in the concurrent IDC, supporting a clonal relationship. Biologic markers varied between the different grades of DCIS. DCIS is heterogeneous, and the progression of DCIS to IDC may be from low-grade DCIS to low-grade IDC and high-grade DCIS to high-grade IDC. This concept is different from the conventional model held for intraepithelial neoplasia in the cervix, vulva, vagina, and skin, in which there is increasing severity of in situ atypia (dysplasia) before the development of stromal invasion.

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