About: Ascus is a research topic. Over the lifetime, 568 publications have been published within this topic receiving 12391 citations. The topic is also known as: asci.
TL;DR: Genotyping may improve risk stratification of high‐risk (HR) human papillomavirus (HPV)‐positive women in cervical screening programs; however, prospective data comparing the natural history and carcinogenic potential of individual HR types remain limited.
Abstract: Genotyping may improve risk stratification of high-risk (HR) human papillomavirus (HPV)-positive women in cervical screening programs; however, prospective data comparing the natural history and carcinogenic potential of individual HR types remain limited. A meta-analysis of cross-sectional HR HPV-type distribution in 115,789 HPV-positive women was performed, including 33,154 normal cytology, 6,810 atypical squamous cells of undetermined significance (ASCUS), 13,480 low-grade squamous intraepithelial lesions (LSIL) and 6,616 high-grade SIL (HSIL) diagnosed cytologically, 8,106 cervical intraepithelial neoplasia grade 1 (CIN1), 4,068 CIN2 and 10,753 CIN3 diagnosed histologically and 36,374 invasive cervical cancers (ICCs) from 423 PCR-based studies worldwide. No strong differences in HPV-type distribution were apparent between normal cytology, ASCUS, LSIL or CIN1. However, HPV16 positivity increased steeply from normal/ASCUS/LSIL/CIN1 (20-28%), through CIN2/HSIL (40/47%) to CIN3/ICC (58/63%). HPV16, 18 and 45 accounted for a greater or equal proportion of HPV infections in ICC compared to normal cytology (ICC:normal ratios = 3.07, 1.87 and 1.10, respectively) and to CIN3 (ICC:CIN3 ratios = 1.08, 2.11 and 1.47, respectively). Other HR types accounted for important proportions of HPV-positive CIN2 and CIN3, but their contribution dropped in ICC, with ICC:normal ratios ranging from 0.94 for HPV33 down to 0.16 for HPV51. ICC:normal ratios were particularly high for HPV45 in Africa (1.85) and South/Central America (1.79) and for HPV58 in Eastern Asia (1.36). ASCUS and LSIL appear proxies of HPV infection rather than cancer precursors, and even CIN3 is not entirely representative of the types causing ICC. HPV16 in particular, but also HPV18 and 45, warrant special attention in HPV-based screening programs.
TL;DR: For women with ASCUS, HPV testing was highly sensitive for detecting CIN3 and cancer with dramatically fewer referrals of older women and neither a single HPV test nor repeat cytopathology provides useful triage for women with LSIL.
Abstract: Background: Testing for oncogenic human papillomavirus (HPV) DNA at a 1.0-pg/mL threshold represents a promising approach for colposcopy triage of atypical squamous cells of undetermined significance (ASCUS), but not for low-grade squamous intraepithelial lesions (LSIL). Considering age or viral load could improve colposcopy triage. Methods: We determined the sensitivity for detecting Cervical Intraepithelial Neoplasia 3 (CIN3) and cancer and the percentage of referrals for colposcopy using HPV testing and repeat thinlayer cytopathology in 2198 women with ASCUS and in 848 women with LSIL enrolled in ALTS from November 1996 through December 1998. We analyzed results by age and at two thresholds for HPV load and repeat cytopathology. Results: For ASCUS, the overall sensitivity of HPV testing at 1.0 pg/mL was 96.1% (95% confidence interval [CI] = 92.8 to 99.5%) and varied minimally with age (range, 93.9% to 97.8%). HPV testing at this threshold would refer 31.2% (95% CI = 28.0% to 34.3%) of women aged 29 years or older as compared with more than 65% of younger women. Among women aged 29 years or older with ASCUS, referral for repeat cytopathology of ASCUS had a sensitivity of 90.9% (95% CI = 81.1% to 100.0%) and would refer 50.1% (95% CI = 46.7 to 53.5%). Among all ASCUS, HPV testing using a 10.0-pg/mL threshold decreased sensitivity to 91.5% and referrals to 41.7%. More than 63% of LSIL would have been referred using any strategy achieving 90% sensitivity. Conclusion: For women with ASCUS, HPV testing was highly sensitive for detecting CIN3 and cancer with dramatically fewer referrals of older women. Neither a single HPV test nor repeat cytopathology provides useful triage for women with LSIL. [J Natl Cancer Inst 2002;94:102–7]
TL;DR: ALTS yielded insight into the performance of cytology and histopathology; experienced pathologists differed significantly in their interpretations of cervical abnormalities, especially histologic CIN 1 and cytologic ASCUS.
Abstract: Controversy exists in the United States regarding the proper evaluation and management of low-grade squamous intraepithelial lesion (LSIL) and equivocal (atypical squamous cells of undetermined significance [ASCUS, now ASC-US]) cervical cytologic interpretations. To address this issue, the National Cancer Institute initiated the ASCUS-LSIL Triage Study (ALTS). ALTS is a multicenter, randomized clinical trial designed to evaluate 3 alternative methods of management, namely, immediate colposcopy, cytologic follow-up, and triage by human papillomavirus (HPV) DNA testing. This article summarizes the major findings of ALTS that have been published to date. Patients with ASCUS (n = 3488) or LSIL (n = 1572) were randomly assigned to research arms between November 1996 and December 1998, and were monitored for 2 years. The disease outcome was histologic cervical intraepithelial neoplasia (CIN) 3/cancer. The prevalence of oncogenic HPV was too high to permit effective triage of LSIL using HPV DNA testing by Hybrid Capture 2. However, for the women referred with a cytologic interpretation of ASCUS, HPV triage proved useful, with sensitivity equivalent to immediate colposcopy and a halving of colposcopic referrals. Among older women with ASCUS, HPV testing remained sensitive for detecting CIN 3 and cancer, but the referral percentage was dramatically lower compared to younger women. ALTS yielded insight into the performance of cytology and histopathology; experienced pathologists differed significantly in their interpretations of cervical abnormalities, especially histologic CIN 1 and cytologic ASCUS. Nonetheless, it was possible to distinguish a relatively uncommon type of ASCUS, equivocal for high-grade squamous intraepithelial lesion, that has a high positive predictive value for identifying women with underlying high-grade CIN. Many additional analyses are underway.
TL;DR: The objective of this study was to analyze the diagnostic performance of a newly established immunocytochemical dual‐stain protocol, which simultaneously detects p16INK4a and Ki‐67 expression in cervical cytology samples, for identifying high‐grade cervical intraepithelial neoplasia (CIN2+) in women with Papanicolaou (Pap).
TL;DR: This chapter focuses on Saccharomyces genus and its member species, and the vegetative cells are transformed directly into persistent asci containing one or two, and rarely four, globose to short ellipsoidal ascospores.
Abstract: Publisher Summary This chapter focuses on Saccharomyces genus and its member species The cells of this genus are globose, ellipsoidal, or cylindroidal Vegetative reproduction occurs through multilateral budding, and pseudohyphae may be formed but not septate hyphae The vegetative phase is predominantly diploid (or of higher ploidy) and conjugation occurs on or soon after germination of the ascospores The ascospores are globose to short ellipsoidal, with a smooth wall and usually one to four per ascus The member species of this genus include Saccharomyces barnettii, Saccharomyces bayanus, Saccharomyces castellii, Saccharomyces cerevisiae, and Saccharomyces dairenensis The cells of Saccharomyces barnettii species, after a growth in 5% malt extract at 25° C for three days appear as globose, ovoidal, or elongate The vegetative cells of this species are transformed directly into persistent asci containing one or two, and rarely four, globose to short ellipsoidal ascospores The ascospores were observed on acetate agar usually after 20-40 days at 25° C The cells of Saccharomyces bayanus species, after growth in 5% malt extract for 3 days at 25° C, are globose, ovoidal, or elongate and are usually isolated The vegetative cells are transformed directly into persistent asci containing one to four globose to short ellipsoidal ascospores