BACKGROUND: Cervical squamous cell carcinoma (CESC), the most common subtype of cervical cancer, is primarily caused by the high-risk human papillomavirus (HPV) infection and genetic susceptibility. Single-cell RNA sequencing (scRNA-seq) has been widely used in CESC research to uncover the diversity of cell types and states within tumor tissues, enabling a detailed study of the tumor microenvironment (TME). This technology allows precise mapping of HPV infection in cervical tissues, providing valuable insights into the initiation and progression of HPV-mediated malignant transformation. METHODS: We performed the scRNA-seq to characterize gene expression in tumor tissues and paired adjacent para-cancerous tissues from four patients with early-stage CESC using the 10× Genomics platform. The HPV infection and its subtypes were identified using the scRNA data and viral sequence mapping, and trajectory analyses were performed using HPV+ or HPV- cells. Interactions between different types of keratinized cells and their interactions with other cell types were identified, and pathways and specificity markers were screened for proliferating keratinized cells. The Cancer Genome Atlas (TCGA) dataset was used to verify the prognostic correlation between tumor-specific PI3+S100A7+ keratinocyte infiltration and CESC, and the localization relationship between PI3+S100A7+ keratinocytes and macrophages was verified by immunofluorescence staining. RESULTS: Various types of keratinocytes and fibroblasts were the two cell types with the most significant differences in percentage between the tumor tissue samples and paired adjacent non-cancerous tissue samples in the early stages of CESC. We found that PI3+S100A7+ keratinocytes were associated with early HPV-positive CESC, and PI3+S100A7+ keratinocytes were more abundant in tumors than in adjacent normal tissues in the TCGA-CESC dataset. Analysis of clinical information revealed that the infiltration of PI3+S100A7+ keratinocytes was notably higher in tumors with poor prognosis than in those with good prognosis. Additionally, multiplex immunofluorescence analysis showed a specific increase in PI3+S100A7+ expression within tumor tissues, with PI3+S100A7+ keratinocytes and CD163+ macrophages being spatially very close to each other. In the analysis of cell-cell interactions, macrophages exhibited strong crosstalk with PI3+S100A7+ proliferating keratinocytes in HPV-positive CESC tumors, mediated by tumor necrosis factor (TNF), CCL2, CXCL8, and IL10, highlighting the dynamic and tumor-specific enhancement of macrophage-keratinocyte interactions, which are associated with poor prognosis and immune modulation. Using CIBERSORTx, we discovered that patients with high infiltration of both PI3+S100A7+ proliferating keratinocytes and macrophages had the shortest overall survival. In the analysis of cell-cell interactions, PI3+S100A7+ proliferating keratinocytes and macrophages were found to be involved in highly active pathways that promote differentiation and structure formation, including cytokine receptor interactions, the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway, and TNF signaling pathway regulation. Further subtyping of fibroblast populations identified four subtypes. The C1 group, characterized by its predominance in tumor tissues, is a subtype enriched with cancer-associated fibroblasts (CAFs), whereas the C3 group is primarily enriched in adjacent non-cancerous tissues and consists of undifferentiated cells. Moreover, the distinct molecular and cellular differences between HPV16- and HPV66-associated tumors were demonstrated, emphasizing the unique tumor-promoting mechanisms and microenvironmental influences driven by each HPV subtype. CONCLUSIONS We discovered a heterogeneous population of keratinocytes between tumor and adjacent non-cancerous tissues caused by HPV infection and identified macrophages and specific CAFs that play a crucial role during the early stage in promoting the inflammatory response and remodeling the cancer-promoting TME. Our findings provide new insights into the transcriptional landscape of early-stage CESC to understand the mechanism of HPV-mediated malignant transformation in cervical cancer.
Humans ; Female ; Papillomavirus Infections/genetics* ; Uterine Cervical Neoplasms/genetics* ; Carcinoma, Squamous Cell/pathology* ; Keratinocytes/metabolism* ; Single-Cell Analysis/methods* ; Tumor Microenvironment/genetics*

Persistent infection with high-risk human papillomavirus(HR-HPV) is the primary etiological factor in cervical lesions and cervical cancer. Toll-like receptors(TLRs), as important pattern recognition receptors of the innate immune system, play a key role in the persistence of cervical HR-HPV infection. The "latent pathogen theory" in traditional Chinese medicine(TCM) holds that latent pathogens have both "latent" and "triggered" characteristics, which closely resemble the persistent infection and latent pathogenic potential of cervical HR-HPV. Guided by the "latent pathogen theory" and using contemporary immunological techniques, this paper explores the bidirectional immunomodulatory effects of TLRs in the persistence of cervical HR-HPV infection and their relationship with latent pathogens. The results indicate that TLRs play a crucial role in immune recognition and modulation. Dysregulation and overactivation of TLRs can induce chronic inflammation, allowing cervical HR-HPV to persist and evade immune detection. TLR dysfunction, coupled with a deficiency in healthy Qi that prevents the expulsion of pathogens, is a critical factor in the pathogenicity of latent pathogens. Restoring healthy Qi to modulate the immune functions of TLRs emerges as an important strategy for clearing cervical HR-HPV infection. By harmonizing the spleen and kidney and regulating immune balance, it is possible to reverse cervical HR-HPV infection, providing a scientific basis for clinical research.
Humans ; Toll-Like Receptors/genetics* ; Female ; Papillomavirus Infections/genetics* ; Papillomaviridae/immunology* ; Persistent Infection/genetics* ; Uterine Cervical Neoplasms/immunology* ; Animals ; Medicine, Chinese Traditional ; Cervix Uteri/immunology* ; Human Papillomavirus Viruses

This study primarily aimed to investigate the prevalence of human papillomavirus (HPV) and other common pathogens of sexually transmitted infections (STIs) in spermatozoa of infertile men and their effects on semen parameters. These pathogens included Ureaplasma urealyticum, Ureaplasma parvum, Chlamydia trachomatis, Mycoplasma genitalium , herpes simplex virus 2, Neisseria gonorrhoeae, Enterococcus faecalis, Streptococcus agalactiae, Pseudomonas aeruginosa , and Staphylococcus aureus . A total of 1951 men of infertile couples were recruited between 23 March 2023, and 17 May 2023, at the Department of Reproductive Medicine of The First People's Hospital of Yunnan Province (Kunming, China). Multiplex polymerase chain reaction and capillary electrophoresis were used for HPV genotyping. Polymerase chain reaction and electrophoresis were also used to detect the presence of other STIs. The overall prevalence of HPV infection was 12.4%. The top five prevalent HPV subtypes were types 56, 52, 43, 16, and 53 among those tested positive for HPV. Other common infections with high prevalence rates were Ureaplasma urealyticum (28.3%), Ureaplasma parvum (20.4%), and Enterococcus faecalis (9.5%). The prevalence rates of HPV coinfection with Ureaplasma urealyticum, Ureaplasma parvum, Chlamydia trachomatis, Mycoplasma genitalium , herpes simplex virus 2, Neisseria gonorrhoeae, Enterococcus faecalis, Streptococcus agalactiae , and Staphylococcus aureus were 24.8%, 25.4%, 10.6%, 6.4%, 2.4%, 7.9%, 5.9%, 0.9%, and 1.3%, respectively. The semen volume and total sperm count were greatly decreased by HPV infection alone. Coinfection with HPV and Ureaplasma urealyticum significantly reduced sperm motility and viability. Our study shows that coinfection with STIs is highly prevalent in the semen of infertile men and that coinfection with pathogens can seriously affect semen parameters, emphasizing the necessity of semen screening for STIs.
Humans ; Male ; Infertility, Male/epidemiology* ; Coinfection/microbiology* ; Papillomavirus Infections/virology* ; Adult ; Sexually Transmitted Diseases/complications* ; China/epidemiology* ; Staphylococcus aureus/isolation & purification* ; Chlamydia trachomatis/isolation & purification* ; Prevalence ; Mycoplasma genitalium/isolation & purification* ; Ureaplasma urealyticum/isolation & purification* ; Neisseria gonorrhoeae/isolation & purification* ; Enterococcus faecalis/isolation & purification* ; Streptococcus agalactiae/isolation & purification* ; Herpesvirus 2, Human/genetics* ; Pseudomonas aeruginosa/isolation & purification* ; Semen/virology* ; Sperm Motility ; Spermatozoa/microbiology* ; Human Papillomavirus Viruses

We aim to study the semen carriage of human papillomavirus (HPV) and evaluate its association with patient characteristics. We conduct a single-center cohort study at Amiens University Hospital Center (Amiens, France). From May 1 to October 31, 2021, 461 men consulting for infertility and with semen analysis data were included. Each participant gave his written informed consent for the use of laboratory, demographic, clinical, and lifestyle data. A proportion of the semen samples were sent to a virology laboratory for HPV screening in a polymerase chain reaction (PCR) assay. In univariate and multivariate analyses with a logistic regression model, HPV + and HPV - groups were compared with regard to semen characteristics (including the DNA fragmentation index and the sperm decondensation index) and demographic, clinical, and lifestyle variables. Semen HPV carriage was detected in 22.3% of the patients. High-oncogenic-risk HPV genotypes were predominant (57.6%). Multivariate analysis showed that HPV carriage was significantly associated with the presence of at least one abnormal spermogram dinging (according to the 6 th World Health Organization criteria), with an adjusted odds ratio (OR) of 4.10 (95% confidence interval [CI]: 2.32-7.25, P < 0.001). A statistically significant association was also found for the type of infertility (OR: 1.61, 95% CI: 1.00-2.57, P = 0.05), the presence of varicocele (OR: 3.99, 95% CI: 1.48-10.71, P = 0.01), and a history of cryptorchidism, testicular ectopia, or monorchidism (OR: 3.54, 95% CI: 1.07-11.66, P = 0.04). Infection with a single HPV genotype or multiple HPV genotypes was significantly associated with at least one abnormal spermogram finding for all HPV oncogenic risk groups (OR: 3.93, 95% CI: 2.08-7.41, P < 0.001; and OR: 4.11, 95% CI: 1.58-10.68, P = 0.01, respectively). The association between sperm HPV carriage and the risk of infertility was statistically significant in a multivariate analysis (OR: 5.63, 95% CI: 3.16-10.01, P < 0.001) and after adjustment for the propensity score (OR: 6.10, 95% CI: 3.33-11.21, P < 0.001). Our results suggest that semen HPV carriage has an impact on male fertility. Sperm screening for HPV might be a useful addition to the work-up for male infertility.
Humans ; Male ; Adult ; Infertility, Male/epidemiology* ; Papillomavirus Infections/complications* ; Semen/virology* ; Semen Analysis ; Prevalence ; Papillomaviridae/genetics* ; Cohort Studies ; Spermatozoa/virology* ; Middle Aged ; France/epidemiology* ; Human Papillomavirus Viruses

Objective: To investigate the natural regression and related factors of high-grade squamous intraepithelial lesion (HSIL) in the cervix of childbearing age women, and to evaluate the applicability of conservative management for future fertility needs. Methods: This study included 275 patients of reproductive age with fertility needs, who were diagnosed as HSIL by biopsy from April 30, 2015 to April 30, 2022, including 229 cases (83.3%) cervical intraepithelial neoplasia (CIN) Ⅱ and 46 cases (16.7%) CIN Ⅱ-Ⅲ. They were followed-up without immediate surgery in the First Affiliated Hospital of Nanjing Medical University. The median follow-up time was 12 months (range: 3-66 months). The regression, persistence and progression of lesions in patients with HSIL were analyzed during the follow-up period, the influencing factors related to regression and the time of regression were analyzed. Results: (1) Of the 275 HSIL patients, 213 cases (77.5%, 213/275) experienced regression of the lesion during the follow-up period. In 229 CIN Ⅱ patients, 180 cases (78.6%) regressed, 21 cases (9.2%) persisted, and 28 cases (12.2%) progressed. In 46 CIN Ⅱ-Ⅲ patients, 33 cases (71.7%) regressed, 12 cases (26.1%) persisted, and 1 case (2.2%) progressed to invasive squamous cell carcinoma stage Ⅰ a1. There was no significant difference in the regression rate between the two groups (χ²=1.03, P=0.309). (2) The average age at diagnosis, age <25 years old at diagnosis were independent influencing factor of HSIL regression in univariate analysis (all P<0.05). There was no significant difference between HSIL regression and pathological grading, the severity of screening results, human papillomavirus (HPV) genotype, colposcopy image characteristics, number of biopsies during follow-up and pregnancy experience (all P>0.05). (3) The median regression times for patients aged ≥25 years and <25 years at diagnosis were 15 and 12 months, respectively. Kaplan-Meier analysis showed that age ≥25 years at diagnosis significantly increased the median regression time compared to <25 years (χ²=6.02, P=0.014). Conclusions: For HSIL patients of childbearing age, conservative management without immediate surgical intervention is preferred if CINⅡ is fully evaluated through colposcopy examination. Age ≥25 years at diagnosis is a risk factor affecting the prognosis of HSIL patients.
Pregnancy ; Humans ; Female ; Adult ; Cervix Uteri/pathology* ; Uterine Cervical Neoplasms/pathology* ; Uterine Cervical Dysplasia/pathology* ; Biopsy ; Colposcopy/methods* ; Squamous Intraepithelial Lesions/pathology* ; Carcinoma in Situ/pathology* ; Papillomaviridae/genetics* ; Papillomavirus Infections/diagnosis* ; Squamous Intraepithelial Lesions of the Cervix/pathology*

Humans ; Squamous Cell Carcinoma of Head and Neck ; RNA, Messenger ; Immunohistochemistry ; Papillomavirus Infections/diagnosis* ; Oncogene Proteins, Viral/genetics* ; Head and Neck Neoplasms ; Cyclin-Dependent Kinase Inhibitor p16 ; Papillomaviridae ; Papillomavirus E7 Proteins/genetics* ; DNA, Viral

Objective: To explore the characteristics and correlations of vaginal flora in women with cervical lesions. Methods: A total of 132 women, including 41 women diagnosed with normal cervical (NC), 39 patients with low-grade cervical intraepithelial neoplasia (CIN 1), 37 patients with high-grade cervical intraepithelial neoplasia (CIN 2/3) and 15 patients with cervical squamous cell carcinoma (SCC), who came from the gynecological clinic of Second Hospital of Shanxi Medical University during January 2018 to June 2018, were enrolled in this study according to the inclusive and exclusive criteria strictly. The vaginal flora was detected by 16S rDNA sequencing technology. Co-occurrence network analysis was used to investigate the Spearman correlations between different genera of bacteria. Results: The dominant bacteria in NC, CIN 1 and CIN 2/3 groups were Lactobacillus [constituent ratios 79.4% (1 869 598/2 354 098), 63.6% (1 536 466/2 415 100) and 58.3% (1 342 896/2 301 536), respectively], while Peptophilus [20.4% (246 072/1 205 154) ] was the dominant bacteria in SCC group. With the aggravation of cervical lesions, the diversity of vaginal flora gradually increased (Shannon index: F=6.39, P=0.001; Simpson index: F=3.95, P=0.012). During the cervical lesion progress, the ratio of Lactobacillus gradually decreased, the ratio of other anaerobes such as Peptophilus, Sneathia, Prevotella and etc. gradually increased, and the differential bacteria (LDA score >3.5) gradually evolved from Lactobacillus to other anaerobes. The top 10 relative abundance bacteria, spearman correlation coefficient>0.4 and P<0.05 were selected. Co-occurrence network analysis showed that Prevotella, Peptophilus, Porphyrinomonas, Anaerococcus, Sneathia, Atopobium, Gardnerella and Streptococcus were positively correlated in different stages of cervical lesions, while Lactobacillus was negatively correlated with the above anaerobes. It was found that the relationship between vaginal floras in CIN 1 group was the most complex and only Peptophilus was significantly negatively correlated with Lactobacillus in SCC group. Conclusions: The increased diversity and changed correlations between vaginal floras are closely related to cervical lesions. Peptophilus is of great significance in the diagnosis, prediction and early warning of cervical carcinogenesis.
Female ; Humans ; Vagina/microbiology* ; Uterine Cervical Neoplasms/genetics* ; Uterine Cervical Dysplasia ; Cervix Uteri ; Lactobacillus/genetics* ; Papillomavirus Infections

Objective: To analyze the characteristics of human papillomavirus (HPV) infection and the distribution of HPV subtypes in Shijiazhuang, Hebei Province, and to explore the application evaluation of multiple PCR capillary electrophoresis fragment analysis for HPV typing test. Methods: A population-based cross-sectional study was conducted among 434 women (age range 17 to 74 years old, 260 patients and 174 physical examinations) included from May to August 2022 in Hebei General Hospital. HPV typing was detected by multiple PCR-capillary electrophoresis fragment analysis. Using the multiple fluorescence quantitative PCR kit as a reference, Chi-square test was used to analyze the diagnostic effect of multiple PCR-capillary electrophoresis fragment analysis, and the consistency was analyzed by Kappa value. Results: The total HPV infection rate was 45.85%(199/434), including 35.48% (154/434) of high-risk HPV (HR-HPV), 3.92% (17/434) of low-risk HPV (LR-HPV), 6.45% (28/434) of HR-HPV and LR-HPV mixed infection, 27.88% (121/434) of single type HPV and 17.97% (78/434) of multi type HPV. HPV52 (9.68%, 42/434), HPV16 (6.91%, 30/434), and HPV58 (6.91%, 30/434) are common HPV subtypes. The positive rate of physical examination was 45.40% (79/174), which was slightly lower than that of patients 46.15% (120/260), there was no significant difference (χ²=0.024,P>0.05). The highest infection rate in the 17-30 age group was 54.76% (46/84), and there was no statistical difference among the age groups(χ²=4.123,P>0.05). The sensitivity and specificity of multiplex PCR capillary electrophoresis fragment analysis were 92.96% and 94.04%, respectively, and Kappa value was 0.870, with the multiplex fluorescent quantitative PCR as the reference. Conclusion: HPV infection may appear younger, and the positive rate of HR-HPV infection is the highest, with HPV52, 16, 58 as the main infection subtypes. The detection results of multiplex PCR capillary electrophoresis fragment analysis method are highly consistent with those of multiplex fluorescent quantitative PCR method, which is suitable for HPV DNA typing.
Humans ; Female ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Uterine Cervical Neoplasms ; Multiplex Polymerase Chain Reaction ; Papillomavirus Infections/diagnosis* ; Cross-Sectional Studies ; Genotype ; Papillomaviridae/genetics*

Objective: To study the diagnostic value of different detection markers in histological categories of endocervical adenocarcinoma (ECA), and their assessment of patient prognosis. Methods: A retrospective study of 54 patients with ECA in the Cancer Hospital, Chinese Academy of Medical Sciences from 2005-2010 were performed. The cases of ECA were classified into two categories, namely human papillomavirus-associated adenocarcinoma (HPVA) and non-human papillomavirus-associated adenocarcinoma (NHPVA), based on the 2018 international endocervical adenocarcinoma criteria and classification (IECC). To detect HR-HPV DNA and HR-HPV E6/E7 mRNA in all patients, we used whole tissue section PCR (WTS-PCR) and HPV E6/E7 mRNA in situ hybridization (ISH) techniques, respectively. Additionally, we performed Laser microdissection PCR (LCM-PCR) on 15 randomly selected HR-HPV DNA-positive cases to confirm the accuracy of the above two assays in identifying ECA lesions. Receiver operating characteristic (ROC) curves were used to analyze the efficacy of markers to identify HPVA and NHPVA. Univariate and multifactorial Cox proportional risk model regression analyses were performed for factors influencing ECA patients' prognoses. Results: Of the 54 patients with ECA, 30 were HPVA and 24 were NHPVA. A total of 96.7% (29/30) of HPVA patients were positive for HR-HPV DNA and 63.3% (19/30) for HR-HPV E6/E7 mRNA, and 33.3% (8/24) of NHPVA patients were positive for HR-HPV DNA and HR-HPV E6/E7 mRNA was not detected (0/24), and the differences were statistically significant (P<0.001). LCM-PCR showed that five patients were positive for HR-HPV DNA in the area of glandular epithelial lesions and others were negative, which was in good agreement with the E6/E7 mRNA ISH assay (Kappa=0.842, P=0.001). Analysis of the ROC results showed that the AUC of HR-HPV DNA, HR-HPV E6/E7 mRNA, and p16 to identify HPVA and NHPVA were 0.817, 0.817, and 0.692, respectively, with sensitivities of 96.7%, 63.3%, and 80.0% and specificities of 66.7%, 100.0%, and 58.3%, respectively. HR-HPV DNA identified HPVA and NHPVA with higher AUC than p16 (P=0.044). The difference in survival rates between HR-HPV DNA (WTS-PCR assay) positive and negative patients was not statistically significant (P=0.156), while the difference in survival rates between HR-HPV E6/E7 mRNA positive and negative patients, and p16 positive and negative patients were statistically significant (both P<0.05). Multifactorial Cox regression analysis showed that International Federation of Obstetrics and Gynecology (FIGO) staging (HR=19.875, 95% CI: 1.526-258.833) and parametrial involvement (HR=14.032, 95% CI: 1.281-153.761) were independent factors influencing the prognosis of patients with ECA. Conclusions: HR-HPV E6/E7 mRNA is more reflective of HPV infection in ECA tissue. The efficacy of HR-HPV E6/E7 mRNA and HR-HPV DNA (WTS-PCR assay) in identifying HPVA and NHPVA is similar, with higher sensitivity of HR-HPV DNA and higher specificity of HR-HPV E6/E7 mRNA. HR-HPV DNA is more effective than p16 in identifying HPVA and NHPVA. HPV E6/E7 mRNA and p16 positive ECA patients have better survival rates than negative.
Female ; Humans ; Papillomavirus Infections/diagnosis* ; Retrospective Studies ; Uterine Cervical Neoplasms/pathology* ; Prognosis ; Oncogene Proteins, Viral/genetics* ; Human Papillomavirus Viruses ; Adenocarcinoma/pathology* ; RNA, Messenger/genetics* ; Papillomaviridae/genetics* ; RNA, Viral/genetics*

Objective: To investigate the clinicopathological features of verrucous type (squamous) dysplasia of esophagus. Methods: The clinicopathological data of 18 verrucous type dysplasia of esophagus patients in the 989th Hospital of the Joint Logistics Support Force of the People's Liberation Army (formerly 152 Central Hospital) and Beijing Chaoyang Hospital Affiliated to Capital Medical University from 2009 to 2021 were retrospectively collected. The histomorphologic characteristics and immunophenotype were observed, and human papillomavirus (HPV) genotyping was detected by PCR-fluorescence probe. The relevant literature was reviewed. Results: The median age of the 18 patients was 68 years (range 53-76 years); there were 13 males and 5 females. There were four cases in the upper esophagus, seven in the middle esophagus and seven in the lower esophagus. The median diameter of the lesion was 18 mm (range 6-54 mm). According to the Paris Classification, 11 cases were 0-Ⅱa, one case was 0-Ⅱa+Ⅰ, five cases were 0-Ⅱb, and one case was 0-Ⅱb+Ⅰ. White light endoscopy showed that the surface of the lesion was white plaque, red areas between the plaques, and papillary surface structure could be seen. In narrow-band imaging, some mucosal areas of lesions were opaque or patchy and light brown, and papillary microsurface structures were different in shapes and sizes. Intraepithelial microvessels were elongated, dilated, twisted and varied in diameter. Lugol iodine stain showed nil to faint staining. Histologically, the atypia cells were large with rounded to irregular nuclei, coarse chromatin, mitotic figures, and abundant eosinophilic cytoplasm. The basal cells showed increased atypia, crowding, increased nuclear-cytoplasmic ratio, and active mitosis. The cells were arranged haphazardly. Single cell keratinization, binuclear cells, and hollow-out-like cells, as well as surface epithelial keratinization and parakeratosis were observed in three cases. There were obvious verrucous or papillary structures in the epithelial layer. Five patients had local verrucous carcinoma. Immunohistochemical staining showed that the mutant expression of p53 protein in 6/10 cases; p16 was positive in 5/10 cases; abnormal Ki-67 distribution pattern in 10/10 cases. HPV was negative in all 10 cases tested. The original pathologic diagnosis of preoperative biopsy was high-grade dysplasia in 8 cases, low-grade dysplasia in 6 cases and atypical squamous epithelial cells in 4 cases. Conclusions: Esophageal verrucous dysplasia tumor cells are well differentiated with obvious verrucous or papillary structures. The unique morphological features suggest that it represents a histological subtype of esophageal squamous high-grade dysplasia and it is a precursor of verrucous carcinoma. Its preoperative biopsy diagnosis is challenging.
Humans ; Middle Aged ; Aged ; Papillomavirus Infections ; Retrospective Studies ; Carcinoma, Verrucous/genetics* ; Carcinoma, Squamous Cell