A selection of normal human tissues was investigated for the presence of lamins B1, B2, and A-type lamins, using a panel of antibodies specific for the individual lamin subtypes. By use of immunoprecipitation and two-dimensional immunoblotting techniques we demonstrated that these antibodies do not cross-react with other lamin subtypes and that a range of different phosphorylation isoforms is recognized by each antibody. The lamin B2 antibodies appeared to decorate the nuclear lamina in all tissues examined, except hepatocytes, in which very little lamin B2 expression was observed. In contrast to previous studies, which suggested the ubiquitous expression of lamin B1 in mammalian tissues, we show that lamin B1 is not as universally distributed throughout normal human tissues as was to be expected from previous studies. Muscle and connective tissues are negative, while in epithelial cells lamin B1 seemed to be preferentially detected in proliferating cells. These results correspond well with those obtained for lamin B1 in chicken tissues. The expression of A-type lamins is most prominent in well-differentiated epithelial cells. Relatively undifferentiated and proliferating cells in epithelia showed a clearly reduced expression of A-type lamins. Furthermore, most cells of neuroendocrine origin as well as most hematopoietic cells were negative for A-type lamin antibodies.

Cervical intraepithelial neoplasia (CIN I, II, and III) and cases of CIN III associated with micro-invasive cervical carcinoma (CIN III & mCA) were analysed for evidence of episomal or integrated human papillomavirus (HPV) 16/18 DNA by fluorescence in situ hybridization (FISH). In parallel, numerical aberrations of chromosomes 1, 17, and X were determined in these lesions as indicators of genomic instability. HPV 16/18 DNA was present in 2 of 12 CIN I, 19 of 23 CIN II/III, and 10 of 12 CIN III & mCA. None of the CIN I and only two of the 19 HPV 16/18-positive solitary CIN II/III showed an integrated HPV pattern. However, all ten cases of HPV-positive CIN III & mCA showed this pattern. Transition of CIN II/III to CIN III & mCA therefore correlates strongly with viral integration (p<0.001). Chromosomal aberrations were detected in 23 of 31 HPV 16/18-positive lesions (14 solitary CIN I-III and nine CIN III & mCA) and 5 of 16 HPV-negative lesions. Nine of 21 HPV 16/18-positive solitary CIN I-III showed tetrasomy for all chromosomes tested, while trisomies for a single chromosome were seen in a further five of these HPV-positive lesions. In eight of ten HPV-positive CIN III & mCA, predominantly aneusomies and/or polysomies were detected. A significant correlation (p<0.02) was found between the chromosome copy number and the physical status of HPV, indicating that in its episomal form HPV induces genomic changes such as tetrasomies and single trisomies, while HPV integration correlates with aneusomies and polysomies, predominantly detected in CIN III & mCA. These data indicate that integration of HPV 16/18 DNA is a pivotal step in the transition of CIN to micro-invasive carcinoma.

Recently proposed events associated with the progression of cervical intraepithelial neoplasia (CIN) 2/3 to cervical carcinoma include integration of human papillomavirus (HPV) into the host genome, genomic instability, and an increase in chromosome 3q copy number. In particular, the gene coding for the RNA component of telomerase (TERC) at 3q26 has been implicated as a possible candidate gene. Since it is not known to date how these events are temporally related during cervical carcinogenesis, the aim of the present study was to assess the correlation between TERC gene copy number and the physical status of HPV during progression in cervical neoplasia. Solitary precursor lesions of the uterine cervix (CIN 2/3, n = 17), lesions associated with a micro-invasive carcinoma (CIN 3&mCA, n = 13), and advanced invasive carcinomas (invCA, n = 7) were analysed by fluorescence in situ hybridization (FISH) to determine the physical status of the virus and TERC gene copy number. The TERC gene was increasingly gained with progression of CIN 2/3 (3 of 17) through CIN 3&mCA (7 of 13) to invCA (5 of 7). In the lesions exhibiting gain of TERC, the virus was predominantly integrated. This was seen in eight of ten diploid lesions, indicating that these events can occur prior to aneuploidization and are strongly associated with the progression of CIN 3 to mCA and invCA (p < 0.001). With progression to carcinoma, a number of these lesions show polyploidization, resulting in aneuploidy and high TERC gene copy numbers. In conclusion, genomic integration of oncogenic HPV and gain of the human telomerase gene TERC appear to be important associated genetic events in the progression of uterine cervical dysplasia to invasive cancer.

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