D. V. Coleman

Damage to DNA in cervical epithelium related to smoking tobacco

OBJECTIVE--To determine whether tobacco smoking causes increased DNA modification (adducts) in human cervical epithelium. DESIGN--Comparison of DNA adducts measured by the technique of postlabelling with phosphorus-32 in normal ectocervical epithelium of smokers and non-smokers. A questionnaire on smoking habit and a urinary cotinine assay were used to identify smokers and non-smokers. SETTING--Cytology unit in large teaching hospital. SUBJECTS--39 women (11 current smokers, seven former smokers, and 21 who had never smoked) undergoing gynaecological treatment (colposcopy or hysterectomy). Nineteen members of staff who did not smoke as controls. INTERVENTIONS--Biopsy of normal ectocervical epithelium. Urine sample. MAIN OUTCOME MEASURES--Measurement of DNA adducts in cervical epithelial tissue of smokers and non-smokers. Smoking habit derived from results of questionnaire and urinary cotinine:creatinine ratio. Proportion of adducts in women with abnormal and normal results of cervical smear test. RESULTS--DNA samples from smokers (identified from questionnaire) had significantly higher median proportions of DNA adducts that non-smokers (4.62 (95% confidence interval 4.04 to 7.74) v 3.47 (2.84 to 4.78) adducts/10(8) nucleotides; p = 0.048). Exclusion of women whose urinary cotinine:creatinine ratio did not confirm their self reported smoking habit (smoker or non-smoker) increased this difference (4.7 (3.85 to 8.08) v 3.52 (2.32 to 4.95) adducts/10(8) nucleotides; p = 0.03). Women who had abnormal results of cervical smear tests had significantly higher proportions of adducts than those with normal results (4.7 (3.90 to 8.13) v 3.47 (3.06 to 5.36) adducts/10(8) nucleotides; p = 0.03). CONCLUSIONS--Tobacco smoking by women leads to increased modification of DNA in cervical epithelium, suggesting biochemical evidence consistent with smoking as a cause of cervical cancer.

Presence of human papillomavirus DNA sequences in cervical intraepithelial neoplasia.

Twenty two patients referred to a district colposcopy clinic because of an abnormal cervical cytology report or a suspicious cervix and found to have a cervical epithelial abnormality were studied. The techniques of cytology, histology, immunohistochemistry, and DNA-DNA hybridisation were used to detect infection by human papillomavirus. Using an indirect immunoalkaline phosphatase technique human papillomavirus antigen was found in biopsy specimens from six of the 22 patients and DNA of papillomavirus type 6 in biopsy specimens from 13 of these women, including four out of six whose histological diagnosis was cervical intraepithelial neoplasia grade 3. In eight cases where cytological, colposcopical, and histological investigations all indicated the presence of wart virus infection, papillomavirus type 6 DNA was found in seven. Papillomavirus type 6 DNA was found in more than half of the proved cases of cervical intraepithelial neoplasia. The presence of this viral DNA in women with no cervical abnormality is to be studied.

Demonstration of smoking-related DNA damage in cervical epithelium and correlation with human papillomavirus type 16, using exfoliated cervical cells

Smoking is a known aetiological risk factor for cervical cancer. Smoking-related DNA damage (DNA adducts), in cervical epithelial cells, has recently been demonstrated to suggest a causal role in the development of cervical cancer. Human papillomavirus 16 (HPV 16) is a known oncogenic virus and is also implicated as a cause of cervical cancer. It has been suggested that both smoking and HPV may act synergistically in the development of cervical cancer. We have investigated the cervical DNA adduct level and the prevalence of HPV 16 (using polymerase chain reaction) in women who had normal cervical cytology. Both the DNA adduct assay and the HPV assay were carried out on exfoliated cervical cells recovered from cervical scrapes. In 87% of the cases there was enough DNA from the exfoliative cervical cells to analyse for DNA adducts. Smokers had higher DNA adduct levels than non-smokers (P = 0.002), confirming the previous data from cervical biopsy samples. Forty-two per cent of the specimens were found to be HPV 16 positive. There was no significant difference in smoking-related DNA damage (DNA adduct levels) between HPV-positive and HPV-negative smokers. This suggests that smoking DNA damage does not augment HPV infectivity. These results do not, therefore, support the molecular synergism theory.

Assessment of a transcervical aspiration technique for chorionic villus biopsy in the first trimester of pregnancy.

Summary. A cannula attached to a syringe was passed through the cervical canal into the uterine cavity in an attempt to aspirate chorionic villi just before termination of a first trimester pregnancy in 82 patients. Chorionic villi were obtained from 40% of these patients. In view of the value of this technique for the first trimester diagnosis of genetic disorder, development of the technique and further trials of transcervical aspiration of chorionic villi would seem warranted.

The prevalence of human papillomavirus antigen in patients with cervical intraepithelial neoplasia.

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The effect of interferon on human papillomaviruses associated with cervical intraepithelial neoplasia

Summary. A double‐blind, placebo‐controlled, trial of leucocyte interferon showed that, contrary to previous reports, interferon had no significant effect on cervical intraepithelial neoplasia (CIN) when applied topically in a geld. DNA hybridization of cervical scrapes was used to monitor the effect of interferon on the human papillomaviruses (HPV) associated with CIN. There was, however, no significant difference in the expression of HPV 6 or 16 in the cervical epithelium of patients treated with interferon compared with those given a placebo. By using superficial cells scraped from the surface of the cervical epithelium as a source of DNA for viral studies, we were able to investigate the relation between HPV and CIN without interfering withthe natural history of the disease. HPV 16 was detected in lesions which persisted while HPV 6 only was detected in one lesion that regressed. Regression was clearly associated with reduction in the number of copies of viral DNA per cell in this case. Dual infection with HPV types 6 and 16 were recorded in two patients with persistent lesions. In one patient, hybridization studies indicated that infectionwith HPV 16 could have occurred after infection with type 6 was established, and it is postulated that this may have changed the nature of the cervical lesion.

Colposcopy in the diagnosis of papillomavirus infection of the uterine cervix

Summary. Morphological criteria are described for the diagnosis of papillomavirus lesions at colposcopy. Using these criteria, evidence of cervical papillomavirus infection was found in 58 (29.0%) of 200 women referred for colposcopy because of an abnormal cytology report. Directed biopsies were obtained from 152 of these patients and histological changes suggestive of papillomavirus infection were found in 47 (30.9%); additional biopsy material from 139 was studied using an immunohisto‐chemical technique and human papillomavirus antigen was demonstrated in 28 (20.1%). Comparison between the colposcopic results and those obtained by histology suggests that whereas it is not possible to make a distinction at colposcopy between lesions due to papillomavirus and those of cervical intraepithelial neoplasia, it is possible to identify those epithelial abnormalties that are most likely to be associated with a papillomavirus infection.

AN EVALUATION OF CYTOLOGY IN THE DIAGNOSIS OF HERPES SIMPLEX VIRUS INFECTION AND CYTOMEGALOVIRUS INFECTION OF THE CERVIX UTERI

A cytological and virological study was made to determine the incidence of herpes simplex virus (HSV) infection and cytomegalovirus (CMV) infection of the cervix uteri in 197 women attending a venereal diseases clinic. Cervical cytology was compared with virus isolation as a means of detecting these infections. Herpes simplex virus was isolated from 11 out of 186 women appropriately tested (5.9 per cent) and an additional 5 patients (2.7 per cent) showed only cytological evidence of the infection, giving a combined diagnostic rate of 8.6 per cent. Cytomegalovirus was isolated from 12 out of 145 patients suitably tested (8.3 per cent) and an inclusion‐bearing cell was identified in one of these patients. An association between CMV and multiple genital warts was noticed.

Quality assurance in cervical cancer screening

Objectives. to examine the effectiveness of introducing External Quality Assessment (EQA) into all laboratories which undertake gynaecological cytopathology. to assess pathologists and cytotechnologists regularly for their competence to screen cervical smears, regardless of their standing in the laboratory hierarchy or their experience of gynaecological cytopathology.

Evaluation of proficiency testing as a method of assessing competence to screen cervical smears.

Evaluation of proficiency testing as a method of assessing competence to screen cervical smears