Precancerous changes in the cervix and risk of subsequent preterm birth

Development of a Novel Mouse Model of Spontaneous High-Risk HPVE6/E7-Expressing Carcinoma in the Cervicovaginal Tract

Current preclinical models for cervical cancer lack important clinical and pathologic features. To improve upon these models, we aimed to develop a novel, spontaneous HPV16-expressing carcinoma model that captures major aspects of HPV-associated cancer in the female genital tract. This novel preclinical model features (i) expression of HPV oncogenes E6 and E7 in the tumors in female reproductive tract of mice, (ii) spontaneous progression through high-grade squamous intraepithelial lesion (HSIL) to carcinoma, and (iii) flexibility to model cancers from different high-risk HPV genotypes. This was accomplished by injecting plasmids expressing HPV16 E6/E7-luciferase, AKT, c-myc, and Sleeping Beauty transposase into the cervicovaginal tract of C57BL/6 mice followed by electroporation. Cell lines derived from these tumors expressed HPV16 E6/E7 oncogenes, formed tumors in immunocompetent mice, and displayed carcinoma morphology. In all, this novel HPV-associated cervicogenital carcinoma model and HPV16E6/E7-expressing tumor cell line improves upon current HPV16-E6/E7-expressing tumor models. These tumor models may serve as important preclinical models for the development of therapeutic HPV vaccines or novel therapeutic interventions against HPV E6/E7-expressing tumors. SIGNIFICANCE: This study describes the development of a clinically relevant mouse model of cervicovaginal carcinoma that progresses from high-grade lesions and recapitulates key features of human HPV⁺ cervical cancer.

Perinatal mortality and other severe adverse pregnancy outcomes associated with treatment of cervical intraepithelial neoplasia: meta-analysis

OBJECTIVE

To assess the relative risk of perinatal mortality, severe preterm delivery, and low birth weight associated with previous treatment for precursors of cervical cancer.

DATA SOURCES

Medline and Embase citation tracking from January 1960 to December 2007. Selection criteria Eligible studies had data on severe pregnancy outcomes for women with and without previous treatment for cervical intraepithelial neoplasia. Considered outcomes were perinatal mortality, severe preterm delivery (<32/34 weeks), extreme preterm delivery (<28/30 weeks), and low birth weight (<2000 g, <1500 g, and <1000 g). Excisional and ablative treatment procedures were distinguished.

RESULTS

One prospective cohort and 19 retrospective studies were retrieved. Cold knife conisation was associated with a significantly increased risk of perinatal mortality (relative risk 2.87, 95% confidence interval 1.42 to 5.81) and a significantly higher risk of severe preterm delivery (2.78, 1.72 to 4.51), extreme preterm delivery (5.33, 1.63 to 17.40), and low birth weight of <2000 g (2.86, 1.37 to 5.97). Laser conisation, described in only one study, was also followed by a significantly increased chance of low birth weight of <2000 g and <1500 g. Large loop excision of the transformation zone and ablative treatment with cryotherapy or laser were not associated with a significantly increased risk of serious adverse pregnancy outcomes. Ablation by radical diathermy was associated with a significantly higher frequency of perinatal mortality, severe and extreme preterm delivery, and low birth weight below 2000 g or 1500 g.

CONCLUSIONS

In the treatment of cervical intraepithelial neoplasia, cold knife conisation and probably both laser conisation and radical diathermy are associated with an increased risk of subsequent perinatal mortality and other serious pregnancy outcomes, unlike laser ablation and cryotherapy. Large loop excision of the transformation zone cannot be considered as completely free of adverse outcomes.