A Meta-Analysis on Human Papillomavirus Type Distribution among Women with Cervical Neoplasia in the WHO Eastern Mediterranean Region

Resolution of oncogene-induced senescence markers in HPV-infected cervical cancer tissue

BACKGROUND

Oncogene-Induced Senescence (OIS) is a form of senescence that occurs as a consequence of oncogenic overstimulation and possibly infection by oncogenic viruses. Whether senescence plays a role in the pathogenesis of cervical cancer (CC) is not well understood. Moreover, whether cervical epithelial cells that are part of the premalignant cervical intraepithelial neoplasia (CIN), exhibit markers of OIS in Human Papillomavirus (HPV)-infected tissue, has not been investigated.

METHODS

We utilized a set of patient-derived premalignant and malignant tissue samples to investigate the protein (Ki67 and Lamin B1) and gene (TP53, IL1A, CCL2, and MMP9) expression of several OIS-associated biomarkers using immunohistochemistry (IHC) and qRT-PCR, respectively. Furthermore, we characterized the HPV status of all tissue samples.

RESULTS

Most of the CC samples (34/37) were positive for HPV, mainly HPV-16 which was observed in 62.2% of the CC samples. Among CINs, HPV infection was found in 60.2% of the 32 samples with HPV-16 as the dominant genotype in 58.5% of the CINs. IHC analysis revealed a significant increase in the expression levels of both Ki67 and Lamin B1 proteins in CC tissue compared to CIN. On average, 93% of tumor cells were positive for Ki67 in comparison to only 25% of premalignant cells in CIN samples. Similarly, Lamin B1 expression was observed in 89% of tumor cells in malignant tissue on average, compared to 60% in CIN samples. Importantly, Lamin B1 expression was elevated in nonmalignant cervical tissue suggesting that its downregulation is more predominant in the premalignant state. Furthermore, RT-PCR revealed a significant decrease in the expression of TP53, IL1a, CCL2, and MMP9 markers in CC samples compared to CINs. Specifically, 84% of CC samples showed reduced TP53 expression, 90% showed reduced IL1a expression, 74% showed reduced CCL2 expression, and 76% showed reduced MMP9 expression when compared with their premalignant baseline. Infection of HPV was confirmed in 61% of the tumor tissues while only 25% of the CINs were positive for HPV.

CONCLUSION

This work shall provide an opportunity to further examine the role of OIS in the process of HPV-driven CC development.

Variable Expression of Oncogene-Induced Senescence/SASP Surrogates in HPV-Associated Precancerous Cervical Tissue

Oncogene-induced senescence (OIS) is a form of cellular senescence triggered by oncogenic signaling and, potentially, by infection with oncogenic viruses. The role of senescence, along with its associated secretory phenotype, in the development of cervical cancer remains unclear. Additionally, the expression of the senescence-associated secretory phenotype (SASP) has not yet been explored in cervical premalignant lesions infected by the Human Papilloma Virus (HPV). This study aimed to investigate the expression of OIS and SASP markers in HPV-infected cervical precancerous lesions. We used a set of patient-derived precancerous (n = 32) and noncancerous (chronic cervicitis; n = 10) tissue samples to investigate the gene expression of several OIS (LMNB1, CDKN2A, CDKN2B, and CDKN1A), and SASP (IL1A, CCL2, TGFB1, CXCL8, and MMP9) biomarkers using qRT-PCR. OIS status was confirmed in precancerous lesions based on Lamin B1 downregulation by immunohistochemical staining. HPV status for all precancerous lesions was tested. Most of the noncancerous samples showed high Lamin B1 expression, however, precancerous lesions exhibited significant Lamin B1 downregulation (p < 0.001). Fifty-five percent of the precancerous samples were positive for HPV infection, with HPV-16 as the dominant genotype. Lamin B1 downregulation coincided with HPV E6 positive expression. CDKN2A and CDKN2B expression was higher in precancerous lesions compared to noncancerous tissue, while LMNB1 was downregulated. The SASP profile of premalignant lesions included elevated CXCL8 and TGFB1 and reduced IL1A, CCL2, and MMP9. this work shall provide an opportunity to further examine the role of OIS and the SASP in the process of malignant cervical transformation.

Prevalence and Genotype Distribution of Human Papillomavirus Infection Among Women in Wuhan, China: A Retrospective Study

Purpose

Human papillomavirus (HPV) infection is a prevalent sexually transmitted infection worldwide, with its persistence being a significant factor in the development of cervical cancer and precancerous lesions. Understanding the prevalence and genotypes distribution of HPV can aid in the implementation of more focused strategies for cervical cancer prevention and treatment. This study aimed to investigate the prevalence and genotype distribution of HPV infection among outpatient-based populations in Wuhan, China.

Methods

Our study retrospectively analyzed the results of cervical HPV screening in 14,492 outpatient women. The cervicovaginal infection of 18 high-risk genotypes and 10 low-risk genotypes were analyzed by PCR and reverse dot hybridization techniques.

Results

The overall prevalence of HPV infection in the outpatient female population was 15.33%, with a predominance of single infection and a predominance of dual infection among multiple infections. The top five genotypes in terms of prevalence of HR-HPV and LR-HPV were HPV-52 (3.77%), 53 (1.46%), 16 (1.31%), 58 (1.19%), 39 (1.18%) for HR-HPV, and HPV-54 (1.23%), 61 (1.08%), 81 (1.04%), 42 (0.87%), 44 (0.70%) for LR-HPV. Two peaks of HPV infection prevalence were observed among women under 25 years (22.88%) and over 56 years (24.26%). The prevalence and genotype distribution of HPV infection varied among different outpatient populations, with higher rates of HPV single infection, multiple infections, and infection across all ages observed in the gynecology outpatient population compared to the health check-up population.

Conclusion

This study revealed the HPV prevalence and genotype distribution among different outpatient populations in Wuhan city, which may provide guidance for HPV vaccination and cervical cancer prevention strategies in the region.

Prevalence of human papilloma virus among cervical cancer patients in India: A systematic review and meta-analysis

BACKGROUND

Cervical cancer, predominantly caused by the human papillomavirus (HPV), is a major health challenge in India, with high morbidity and mortality rates. Given India's vast geographic and socio-economic diversity, understanding regional variations in HPV prevalence is crucial for developing targeted and effective public health interventions. This systematic review and meta-analysis were conducted to elucidate the prevalence of HPV among cervical cancer patients in India.

METHODS

A literature search was executed across PubMed, EMBASE, and Web of Science up to December 07, 2023. Observational studies reporting HPV prevalence among cervical cancer patients in India are included. A Modified Newcastle-Ottawa scale was used for quality assessment. A random-effects meta-analysis was used to determine pooled HPV prevalence, and heterogeneity was evaluated using the I² statistic. Subgroup and sensitivity analyses were performed to assess result stability and investigate heterogeneity sources. All statistical analyses were performed using R software version 4.3.

RESULTS

The meta-analysis included 17 studies with a total of 2529 cervical cancer cases, of which 1977 were HPV-positive. The pooled HPV prevalence was 85% (95% CI: 71-92%), with substantial heterogeneity (I² = 94%). Subgroup analysis by geographic zones showed notable differences: South (88%, 95% CI: 76-95%), North (73%, 95% CI: 1-100%), East (99%, 95% CI: 1-100%), Central (71%, 95% CI: 54-84%), and West (77%, 95% CI: 0-100%). Sensitivity analysis demonstrated the consistency of the results, and a reanalysis, excluding influential studies, yielded a prevalence of 82% (95% CI: 67-91%).

CONCLUSION

Our analysis reveals a high prevalence of HPV in cervical cancer patients in India, with significant regional variations. The observed heterogeneity highlights the complexity of HPV epidemiology in India and necessitates further research to explore underlying causes and regional characteristics. Future studies should aim to expand geographic representation and deepen understanding of the factors contributing to the variability in HPV prevalence.

Prevalence and trends of cervical cancer screening among women in Fiji from 2014 to 2018

Introduction

Cervical cancer is the third most common cancer in women both in developed and developing countries. This study aimed to determine the prevalence of cervical cancer and the trends of cervical cancer screening among women who had cervical cancer screening in Suva, Fiji between 2014 and 2018.

Materials and method

This study applied a 5-year retrospective electronic chart review of data from all women attending the Women's Wellness Clinic (WWC) in Suva, Fiji. The women who were selected for this study and screened for cervical cancer were Fijian citizens above 18 years of age and were registered in 2014-2018. A data collection form was used to collect data. The data was analyzed using Statistical Package for Social Sciences (SPSS) version 24; p <0.05 % was considered as the level of significance.

Results

Among the 39,579 women who attended WWC for other family planning services, 12,074 women screened for cervical cancer with a prevalence of 30.5 %. The overall mean age for women screened for cervical cancer was 37.6 (SD ± 11.2). Two-thirds (76.4 %) of the women screened for cervical cancer were less than 46 years of age and 53.9 % were I-taukei. The number of women who came for Pap smear increased in 2015, however, a slight decline was observed in 2016 which was later improved to 35.1 % in 2018. Malignancy was more common in the age range of 42-49 respectively. In this study, women of 46 years and above had an OR of 0.51 (95 % CI: 0.36, 0.72), other ethnicity OR was 1.73 (95 % CI: 1.27, 2.35), and the Muslim religion OR recorded was 1.44 (95 % CI: 1.03, 2.01) which was comparatively considered a high-risk group. Women who are widowed 1.57 (95 % CI: 0.798, 3.11), single 1.29 (95 % CI: 0.87, 1.92) or divorced 1.08 (95 % CI: 0.59, 1.99), employed 1.01 (95 % CI: 0.83, 1.24) and are living in rural areas 1.19 (95 % CI: 0.82, 1.73) are also associated with higher odds of having abnormal results.

Conclusion

Cervical cancer is listed as the first and most common type of cancer in women which is noticeably increasing in Fiji. Even though cervical cancer screening has improved over the years, adequate surveillance systems and ongoing programs should be designed and implemented to increase awareness and monitor the trend of cervical cancer screening in order to reduce cervical cancer prevalence and mortality rates.

Development of a sensitive droplet digital PCR according to the HPV infection specificity in Chinese population

HPV16 and 18 are positively correlated with cervical carcinogenesis. However, HPV prevalence tends to vary according to region, nationality, and environment. The most prevalent high-risk (HR) HPV genotypes are HPV16, 52, 58, 56, 18, 33, and 45), while the low-risk (LR) genotypes are HPV6 and 11 in the Chinese population. Importantly, undetectable low-copy HPV DNA could be an important indicator of integration into the human genome and may be a precursor to cancer progression. The HPV viral load changes dramatically, either increasing or decreasing rapidly during carcinogenesis, and traditional quantitative real-time PCR (qPCR) cannot accurately capture this subtle change. Therefore, in this study, a reliable droplet digital PCR (ddPCR) method was developed to simultaneously detect and quantify HPV genotypes. The ddPCR quantitative results showed high accuracy, sensitivity, and specificity compared to qPCR results employing the same clinical specimens and supplemented the ddPCR assay for HPV52/56/58/6 genotypes according to the infection specificity of the Chinese population. In summary, this procedure is valuable for quantifying HPV DNA, especially under conditions of low template copy number in cervical intraepithelial neoplasia (CIN) and/or cervical cancer. Additionally, this method can dynamically observe the prognosis and outcome of HPV infection and thus be used as an effective means for real-time monitoring of tumor load.

Cost-Benefit Analysis of Human Papillomavirus Vaccine in Iran

Despite increasing global attention to the national human papillomavirus (HPV) immunization program, this program is controversial in Iran. Evidence indicates that HPV vaccination is not cost-effective in Iran. Using cost-effectiveness analysis for decision-making about public health interventions such as vaccination is controversial because its potential benefits may not fit this framework. This study aimed to evaluate the economic effects of the HPV vaccination by cost-benefit analysis (CBA) using bivalent and quadrivalent in Iran in 2020. We performed a CBA from a societal perspective. We used two approaches of the vaccine's economic benefits: willingness to pay by discrete choice experiment and cost of illness. Costs only included the vaccine cost. The cost of two doses of bivalent and quadrivalent vaccines were US $29 and the US $151, respectively (US $1 = IRR 42,000). The benefits of bivalent and quadrivalent vaccines were US $ - 432, US $380 per person using the willingness to pay approach, and they were US $7375 and US $6590 thorough cost-of-illness approach. The cost-benefit ratio (CBR) of bivalent and quadrivalent vaccines was - 15.11 and 2.51 by the willingness to pay approach, and 258.12 and 43.51 by the cost of illness approach. This study confirms the benefits of the national bivalent and quadrivalent vaccination programs and provides reliable evidence for policy-makers programming HPV vaccination.

Potential role of human papillomavirus proteins associated with the development of cancer

Papillomaviruses are viruses with double-stranded DNA that are epitheliotropic and non-enveloped that infects cutaneous epithelial and mucosal cells in a species-specific way in several higher vertebrate species and cause cellular growth."There are around 100 different human papillomaviruses (HPVs)", as "more than 150 HPV types have been isolated and fully sequenced". We classify the probability of cancer development following viral infection with each HPV genotype into two types: "low-risk" and "high-risk." As a result, HPV diagnosis is a critical component of HPV genotype identification and characterization. Based on its activities, we may classify the HPV genome into three regions: the long control region (LCR) or the non-coding upstream regulatory region (URR), the late (L) region, and the early (E) region. Functional proteins are mostly static things that are not inflexible; they have undergone both local and global movements at various times and time ranges. The structural differences between HPV16 and 18 discovered by molecular modeling of the E6 oncoprotein were associated with their carcinogenic characteristics. Similarly, the E6 protein has two sets of C-X-X-C motifs that play significant roles in transformation, transcriptional activation, interactions, and immortalization with other proteins of cells in the host environment. Here, we review the literature regarding the protein mechanisms associated with HPV and how they cause cancer. Unless otherwise noted, it described all protein activities in terms of HPV proteins. The term "papillomaviruses" refers to groups of papillomavirus proteins that have a characteristic in common. HPV proteins can study the genetic influences on pathogenicity and the therapeutic applications of genomics. The future study provides a potential advancement in HPV infections and malignant illnesses to improve preventive and treatment strategies. Patients have been able to conquer this condition using a range of therapies and vaccines that were projected to be effective and robust enough to put an end to the ailment completely. In cancer prevention strategies, HPV vaccination is one of the most effective. It is safe, efficient, and long-lasting.

The E6 Oncoprotein of HPV16 AA-c Variant Regulates Cell Migration through the MINCR/miR-28-5p/RAP1B Axis

The E6 oncoprotein of HPV16 variants differentially alters the transcription of the genes involved in migration and non-coding RNAs such as lncRNAs. The role of the lncRNA MINCR in cervical cancer and its relationship with variants of oncogenic HPV remain unknown. Therefore, the objective of this study was to analyze the effect of the E6 oncoprotein of the AA-c variant of HPV16 in cell migration through the MINCR/miR-28-5p/RAP1B axis. To explore the functional role of MINCR in CC, we used an in vitro model of C33-A cells with exogenous expression of the E6 oncoprotein of the AA-c variant of HPV16. Interfering RNAs performed MINCR silencing, and the expression of miR-28-5p and RAP1B mRNA was analyzed by RT-qPCR. We found that C33-A/AA-c cells expressed MINCR 8-fold higher compared to the control cells. There is an inverse correlation between the expression of miR-28-5p and RAP1B in C33-A/AA-c cells. Our results suggest that MINCR might regulate the expression of RAP1B through the inhibition of miR-28-5p in CC cells expressing the E6 oncoprotein of HPV16 AA-c. We report, for the first time, that the MINCR/miR-28-5p/RAP1B axis positively regulates cell migration in CC-derived cells that express the E6 oncoprotein of the AA-c variant of HPV16.

Trends in Co-circulation of Oncogenic HPV Genotypes in Single and Multiple Infections among Unvaccinated Community

Cocirculation of multiple human papillomavirus (HPV) infections with low, probably high, and high‐risk genotypes are to be associated with various grades of infections and cancer progression. The oncogenic high‐risk HPVs are distributed and cocirculated throughout the world. This study was investigated to identify HPV genotypes related to genital disorders in unvaccinated women. The subjects were referred from clinics to a molecular lab for HPV testing in Iran as a low‐coverage vaccinated country. HPVs DNAs of cervical scrapping and genital tissue specimens of 1,133 un‐vaccinated women were genotyped using an in vitro diagnostic line probe (reverse hybridization) assay. In addition, phylogenetic trees were constructed on 100 MY09/MY11 polymerase chain reaction (PCR) amplicons of common genotypes of HPV L1 gene by Sanger sequencing. The mean age of the population study was 32.7 ± 8.0 and the mean age of HPV‐positive cases was 31.6 ± 7.8. HPV DNA was detected in 57.8% (655/1133) of women subjects and 42.2% (478/1133) of cases were undetected. Among 655 HPV‐positive cases, 639 subjects (56.4%) were related to defined genotypes and 16 subjects (1.4%) were untypeable. The highest prevalence rate of HPV genotypes was identified in the 25–34 years. The top 6 dominant HPVs in single and multiple genotypes were HPV6 (284/655 [43.4%]), HPV16 (111/655 [16.9%]), HPV31 (72/655 [11%]), HPV53 (67/655 [10.2%]), HPV11 (62/655 [9.5%]), and HPV52 (62/655 [9.5%]). Moreover, single, multiple and untypeable HPV genotypes were diagnosed as follows: 1 type (318/655 [48.5%]), 2 types (162/655 [24.8%]), 3 types (83/655 [12.7%]), 4 types (42/655 [6.5%]), more than 5 types (34/655 [5.3%]), and 1.4% un‐typeable subjects. The sequenced partial L1 gene of HPV genotypes (GenBank databases under the accession numbers: MH253467‐MH253566) confirmed and determined the cocirculated HPV genotypes' origins and addressed helpful insights into the future viral epidemiology investigations. Multiple HPV infections and cocirculation of various oncogenic HPV genotypes among the normal population (women and men) with asymptomatic forms are still challenging in unvaccinated communities. The preventive and organized surveillance programs for HPV screening are needed to be considered and compiled by health policy makers of low or unvaccinated countries.

Cervical Screening in North Sardinia (Italy): Genotype Distribution and Prevalence of HPV among Women with ASC-US Cytology

The assessment of human papillomavirus (HPV) genotype dynamics could support the adoption of more tailored preventive actions against cervical cancer. The aim of the study was to describe the prevalence of HPV infection, HPV genotype distribution, and the epidemiological characteristics of women with ASC-US cytology since the introduction of HPV-DNA testing in Sardinia (Italy), (March 2016–December 2020). Specimens were tested by RT-PCR for 14 high-risk HPV genotypes. A total of 1186 patients were enrolled, with a median (IQR) age of 41 (38–48) years. Of these women, 48.1% were positive for at least one HPV genotype; 311 (26.2%) women were vaccinated with a median (IQR) age of 38 (30/47) years. The percentage of prevalence of HPV-16, -31, -66, -56, and -51 was 36.3%, 18.7%, 11.9%, 11.4% and 10.7%, respectively. The highest prevalence of infection was found in women aged <41 years, and single women. Moreover, women aged >41 years (OR: 0.51, 95% CI: 0.31–0.86; p-value: 0.01), having parity (OR: 0.57, 95% CI: 0.34–0.96, p-value: 0.04), and higher educational level (OR: 0.39, 95% CI: 0.18–0.87; p-value: 0.02) were associated with a lower CIN2+ risk. We did not find a significant difference in terms of prevalence of HPV-16 infection between vaccinated and non-vaccinated (18.3% vs. 17.1%; p-value < 0.001). Our results support the adoption of nonavalent HPV-vaccine to prevent the most prevalent infections caused by HPV-16 and -31 genotypes and underscore the need of surveillance to implement tailored vaccination programs and preventive strategies.

Distribution of human papillomavirus in precancerous and cancerous cervical neoplasia in Tunisian women

Background

High-risk human papillomavirus (HR-HPV) are responsible for cervical cancer (CC) which represents the second most prevalent gynecological cancer among Tunisian women. Preventive strategies against CC are based on prophylactic vaccines that have not yet been implemented into the national vaccination program of Tunisia. Therefore, the present study aimed to investigate the HPV genotypes distribution in cervical neoplasia in Tunisian women in order to predict the impact of using current HPV vaccines on cancer prevention in Tunisia.

Methods

A total of 200 formalin-fixed paraffin embedded biopsies were collected in our study. DNA was extracted using Qiagen Mini prep kit. DNA quality was controlled by Beta Globin PCR. Only positive samples for Beta Globin test were used. HPV detection was performed by a nested PCR using PYGMY and GP5+/6+ primers. Genotyping was performed by Reverse Line hybridization using 31 probes.

Results

The mean age of participants was 38.97 years and 75% were over 30 years. Cervical neoplasia distribution according to age showed that CINII/CINIII was observed among women over 30 years old. All samples were positive for Beta Globin PCR. Overall HPV prevalence in cervical lesions was 83% (166/200). HPV was present in 65% of CINI, 82% of CINII/CINIII and 85% of CC. HR-HPV was statistically significantly associated with cervical intraepithelial neoplasia (p < 10^–3). HR-HPV distribution according to lesion grade and cervical cancer showed that HPV16 and HPV18 were present in all lesions. For CINII/CINIII, HPV 35 (37.5%) was the most detected type, followed by HPV18 (33.3%) HPV 45 (28.5%) and HPV 16 (18.9%). HPV 45(57.5%), HPV 18 (53.3%) were the most detected in CC. HPV58, 59, 68 were only detected in CC and associated with HPV45, 18 and HPV16. HPV39, 31, 33, 52, 56 and HPV70 was associated only with CINI.

Conclusions

Our findings can give useful information for vaccine implementation by helping the health policymakers to choose the most appropriate vaccine type in Tunisia.

Leptomeningeal Carcinomatosis of a Poorly Differentiated Cervical Carcinoma Caused by Human Papillomavirus Type 18

Cervical cancer is caused by a persistent infection with high-risk types of Papillomaviruses (hrHPV); HPV16 and HPV18 are associated with about 70% of the cases. In the last decades the introduction of a cervical cancer screening has allowed a decrease in cervical cancer incidence and mortality; regular adhesion to the screening procedures, by pap test or HPV test, and colposcopy, according to the international guidelines, prevents cancer development and allows for diagnosis at the early stages. Nowadays, in industrialized countries, it is not common to diagnose this pathology in advanced stages, and this occurrence is frequently associated with patient’s unattendance of cervical screening programs. We describe a case of delayed diagnosis of cervical cancer, posed only after the onset of the neurological symptoms caused by leptomeningeal metastases, despite a two-year history of abnormal cytology. The endocervical mass was analyzed by immunohistochemistry, and search and typing of HPV sequences was performed by PCR in the meningeal carcinomatous cells. A poorly differentiated squamous cell carcinoma was diagnosed, and HPV18 sequences were detected. This rapidly fatal case highlights the importance of following the evidence-based recommended protocols and the preventive role of the population-based cervical cancer screening programs.

Simultaneous Detection and Viral DNA Load Quantification of Different Human Papillomavirus Types in Clinical Specimens by the High Analytical Droplet Digital PCR Method

Human papillomaviruses (HPVs) are small DNA tumor viruses that mainly infect mucosal epithelia of anogenital and upper respiratory tracts. There has been progressive demand for more analytical assays for HPV DNA quantification. A novel droplet digital PCR (ddPCR) method was developed to simultaneously detect and quantify HPV DNA from different HPV types. DdPCR was initially tested for assay sensitivity, accuracy, specificity as well as intra- and inter-run assay variation employing four recombinant plasmids containing HPV16, HPV18, HPV11, and HPV45 DNAs. The assay was extended to investigate/quantify HPV DNA in Cervical Intraepithelial Neoplasia (CIN, n = 45) specimens and human cell lines (n = 4). DdPCR and qPCR data from clinical samples were compared. The assay showed high accuracy, sensitivity and specificity, with low intra-/inter- run variations, in detecting/quantifying HPV16/18/11/45 DNAs. HPV DNA was detected in 51.1% (23/45) CIN DNA samples by ddPCR, whereas 40% (18/45) CIN tested HPV-positive by qPCR. Five CIN, tested positive by ddPCR, were found to be negative by qPCR. In CIN specimens, the mean HPV DNA loads determined by ddPCR were 3.81 copy/cell (range 0.002-51.02 copy/cell), whereas 8.04 copy/cell (range 0.003-78.73 copy/cell) by qPCR. DdPCR and qPCR concordantly detected HPV DNA in SiHa, CaSki and Hela cells, whereas HaCaT tested HPV-negative. The correlation between HPV DNA loads simultaneously detected by ddPCR/qPCR in CINs/cell lines was good (R 2 = 0.9706, p < 0.0001). Our data indicate that ddPCR is a valuable technique in quantifying HPV DNA load in CIN specimens and human cell lines, thereby improving clinical applications, such as patient management after primary diagnosis of HPV-related lesions with HPV-type specific assays.