A novel highly sensitive and specific flow cytometry system for cervical cancer screening

DNA Flow Cytometry Analysis in Body Cavity Fluids Using Liquid-Based Cytology

BACKGROUND

DNA flow cytometry using LC-1000 is utilized for analyzing cellular and nuclear lengths and DNA content in individual cells with samples in cell preservation solutions to acquire the cell proliferation index (CPIx). This study aimed to evaluate the performance of body cavity fluid cytology using LC-1000. As cell preservation solutions, liquid-based cytology (LBC) by Cellprep (CP) was compared with CelVerse (CeV), specifically designed for the LC-1000.

METHODS

Overall, we evaluated 43 samples (20 malignant and 23 benign) of body cavity fluids suspended in CeV and 59 samples (28 malignant and 31 benign) suspended in CP. The CPIx was compared between malignant and benign cases of CeV and CP. Further, the subject groups were divided according to the SubG1% in a sample.

RESULTS

The CPIx in CeV was 0.14-10.22 (median 0.62) in malignant cases and 0.09-4.64 (median 0.19) in benign cases (p < 0.001); additionally, CP displayed 0.14-9.87 (median 0.84) in malignant cases and 0.11-3.02 (median 0.22) in benign cases (p < 0.001). The area under the curve (AUC) was 0.811 for CeV and 0.776 for CP. The difference in SubG1% between the CeV and CP groups was statistically significant (p < 0.0001) and influenced the AUC in CP.

CONCLUSION

The CPIx in CeV or CP samples using the LC-1000 may be applicable as an objective indicator in body cavity fluid cytology. Samples preserved in CeV provided more consistent results, unaffected by SubG1%, when compared to those stored in CP.

LC-1000 flow cytometry system complements intraoperative peritoneal cytology for pancreatic and biliary tract cancer

BACKGROUND

The exfoliative cell analyzer, LC-1000, is medical device that utilizes the principles of flow cytometry, and might provide digital diagnostic information for cytology using a different approach from conventional cytomorphology. In this study, wae examined the usefulness of the LC-1000 as a diagnostic support system for intraoperative peritoneal lavage cytology and its prognostic impact for pancreatic (PC) and biliary tract cancer (BTC).

METHODS

Patients with PC and BTC who underwent surgical treatment were included. First, we identified useful indicators of LC-1000 and established cutoff values to discriminate positive cytology. Next, we verified the validity of these cutoff values.

RESULTS

In the test set (n = 48), of the LC-1000 indicators examined, only MR-CPIx was significantly different between the negative and positive cytology groups, yielding a cutoff value of 0.86. In the validation set (n = 52), the sensitivity, specificity, positive and negative predictive value of the LC-1000 for cytology results was 1.0, 0.49, 0.11 and 1.0, respectively. In patients who had undergone radical resection, recurrence-free survival rate was significantly higher in the LC-1000 negative group than in the positive group in PC, but not in BTC.

CONCLUSION

The LC-1000 was useful as digital support system for peritoneal cytology, and it might have potential as a prognostic factor for PC.

Cytological characteristics of histological types of lung cancer by cytomorphometric and flow cytometric analyses using liquid-based cytology materials

BACKGROUND

Distinguishing the histological types of lung cancer is essential for determining treatment strategies in clinical practice. In this study, cytomorphological characteristics and proliferative activities were compared among histological types of lung cancer by cytomorphometric and flow cytometric analyses using liquid-based cytology (LBC) samples.

METHODS

Scraped LBC samples from 73 surgically resected specimens were collected between August 2018 and November 2019. Papanicolaou-stained and paired Ki-67-stained slides were used for cytomorphometric analyses. Another sample for each case was analyzed using a flow cytometric system (LC-1000). The cell proliferation index (CPIx) was calculated to evaluate proliferative activity.

RESULTS

In total, 73 cases, including cases of adenocarcinoma (n = 53), squamous cell carcinoma (n = 14), small cell carcinoma (n = 1), large cell neuroendocrine carcinoma (NEC; n = 3), and pleomorphic carcinoma (n = 2) were evaluated. Small cell carcinoma and large cell NEC were categorized into a single group, NEC. The adenocarcinoma group tended to have a larger nuclear area and longer perimeter than other histological types. The NEC group had a considerably higher Ki-67 labeling index and significantly higher CPIx than other histological types (p = .030). A significant positive correlation was observed between the Ki-67 labeling index and CPIx for all cases (r = 0.362, p = .002).

CONCLUSION

The Ki-67 labeling index and flow cytometric analyses focus on proliferative activity for the distinction of histological types of lung cancer, thereby guiding clinical decision-making.

Cytomorphometric and flow cytometric analyses using liquid-based cytology materials in subtypes of lung adenocarcinoma

BACKGROUND

The histological classifications of invasive lung adenocarcinoma subtypes are considered to predict patient prognosis after surgical treatment. The objectives of this study were to evaluate cytomorphological characteristics and proliferative activities among the histological predominant patterns by performing cytomorphometric and flow cytometric analyses using liquid-based cytology materials.

METHODS

Cytological samples fixed by liquid-based cytology preservatives from 53 surgically-resected lung adenocarcinoma specimens were obtained between August 2018 and November 2019. The Papanicolaou-stained and paired Ki-67-stained slides were analyzed for calculating nuclear morphology (nuclear area, nuclear perimeter and nuclear circularity) and Ki-67 labeling index using software. The cell proliferation index (CPIx) was calculated and cellular information including cell cycle stage of tumor cells was obtained by flow cytometry.

RESULTS

The 53 cases included papillary (n = 29), acinar (n = 8), lepidic (n = 5), and solid (n = 4) subtypes, and invasive mucinous adenocarcinoma (n = 7) were also included. In the lepidic pattern, nuclear area (79.6 ± 28.8 μm² ) and perimeter (34.1 ± 6.1 μm) were relatively larger and longer than those of the other predominant patterns. The Ki-67 labeling index of the solid pattern (27.9 ± 12.5%) was highest compared with those of other predominant patterns. There were statistically significant differences in the lepidic versus solid patterns and the papillary versus solid patterns (p = .013 and p = .039, respectively). The calculated mean CPIx of the lepidic and the acinar patterns were approximately two-fold higher than those of the other predominant patterns.

CONCLUSION

By revealing the differences of cytomorphological characteristics, these methodologies might be used for diagnosing cytopathological materials using digital cytopathology.

Scrutinizing high-risk patients from ASC-US cytology via a deep learning model

BACKGROUND

Atypical squamous cells of undetermined significance (ASC-US) is the most frequent but ambiguous abnormal Papanicolaou (Pap) interpretation and is generally triaged by high-risk human papillomavirus (hrHPV) testing before colposcopy. This study aimed to evaluate the performance of an artificial intelligence (AI)-based triage system to predict ASC-US cytology for cervical intraepithelial neoplasia 2+ lesions (CIN2+).

METHODS

More than 60,000 images were used to train this proposed deep learning-based ASC-US triage system, where both cell-level and slide-level information were extracted. In total, 1967 consecutive ASC-US Paps from 2017 to 2019 were included in this study. Histological follow-ups were retrieved to compare the triage performance between the AI system and hrHPV in 622 patients with simultaneous hrHPV testing.

RESULTS

In the triage of women with ASC-US cytology for CIN2+, our system attained equivalent sensitivity (92.9%; 95% confidence interval [CI], 75.0%-98.8%) and higher specificity (49.7%; 95% CI, 45.6%-53.8%) than hrHPV testing (sensitivity: 89.3%; 95% CI, 70.6%-97.2%; specificity: 34.3%; 95% CI, 30.6%-38.3%) without requiring additional patient examination or testing. Additionally, the independence of this system from hrHPV testing (κ = 0.138) indicated that these 2 different methods could be used to triage ASC-US as an alternative way.

CONCLUSION

This de novo deep learning-based system can triage ASC-US cytology for CIN2+ with a performance superior to hrHPV testing and without incurring additional expenses.

A Clinical Trial to Verify the Efficiency of the LC-1000 Exfoliative Cell Analyzer as a New Method of Cervical Cancer Screening

OBJECTIVE

The exfoliative cell analyzer, LC-1000 (Sysmex Corporation, Japan), is a medical device that presents the cell proliferation index and 23 research parameters as indicators of cellular proliferative potential. The objective was to evaluate the clinical usability of qualitative assessment by LC-1000 compared with cytology, the human papillomavirus (HPV) test, and histology as gold standard.

STUDY DESIGN

Women that visited 3 sites between July 2015 and March 2017 were registered. The primary endpoint in this study was the comparison between LC-1000 measurement and HPV test for sensitivity and specificity for cervical intraepithelial neoplasia 2+ (CIN2+). A tree model algorithm was newly constructed by a statistical method and its relationship with histological results was evaluated.

RESULTS

The sensitivity and specificity of LC-1000 were 78.3 and 74.1%, while those of the HPV test were 94.7 and 85.4%, respectively. A tree model comprising five categories was constructed. The proportion of advanced lesions was higher with the change in the rank classification results from 1 to 5. The positive predictive values of CIN2+ in the categories 4 and 5 were high. Despite the small number of subjects, cancer was undetected in categories 1 and 2. In addition, the comparison with follow-up results in 19 women assessed as CIN1 showed that the rate of progression in the categories 3-5 was 50% (7/14); progression in the categories 1 and 2 was 0% (0/5).

CONCLUSIONS

LC-1000 may be useful for cervical cancer screening as an index to qualitatively evaluate CIN and cancer based on the changes in characteristics of cells.

Evaluation of the LC-1000 Flow Cytometry Screening System for Cervical Cancer Screening in Routine Health Checkups

OBJECTIVE

This study evaluated the performance of a flow cytometry system (LC-1000) in screening cervical precancerous lesions at routine health checkups.

STUDY DESIGN

In total, 928 health examinees were enrolled at 16 health promotion centers in 13 Korean cities between 2016 and 2017. All participants underwent liquid-based cervical cytology and flow cytometry testing to determine the cell proliferation index (CPIx).

RESULTS

The positivity rate of the LC-1000 system increased with the severity of the cervical cytology findings (p for trend < 0.001). When low-grade squamous intraepithelial lesion (LSIL) or higher (including LSIL, high-grade squamous intraepithelial lesion [HSIL], and atypical squamous cells without excluding HSIL [ASC-H]) was defined as gold-standard positivity, the sensitivity, specificity, PPV, and NPV of LC-1000 were 75.3% (95% confidence interval [CI], 66.8-83.7), 58.5% (95% CI, 55.2-61.9), 18.1% (95% CI, 14.5-21.8), and 95.1% [95% CI, 93.2-97.0], respectively. The median CPIx increased significantly from normal cytology to HSIL (p < 0.001). The median CPIx was higher in high-risk human papillomavirus (HR-HPV)-positive cases than in HR-HPV-negative cases (0.23 vs. 0.17, p < 0.001), while it did not differ between HR-HPV-positive and HR-HPV-negative cases with normal cytology findings (0.16 vs. 0.16, p = 0.700).

CONCLUSION

The LC-1000 system is potentially useful for screening cervical precancer and cancer, especially when excluding normal or ASC of undetermined significance cases in routinely screened populations.

Evaluation of immunity to varicella zoster virus with a novel double antigen sandwich enzyme-linked immunosorbent assay

Varicella is a highly contagious disease caused by primary infection of Varicella zoster virus (VZV). Varicella can be severe or even lethal in susceptible adults, immunocompromised patients and neonates. Determination of the status of immunity to VZV is recommended for these high-risk populations. Furthermore, measurement of population immunity to VZV can help in developing proper varicella vaccination programmes. VZV glycoprotein E (gE) is an antigen that has been demonstrated to be a highly accurate indicator of VZV-specific immunity. In this study, recombinant gE (rgE) was used to establish a double antigen sandwich enzyme-linked immunosorbent assay (ELISA). The established sandwich ELISA showed high specificity and sensitivity in the detection of human sera, and it could detect VZV-specific antibodies at a concentration of 11.25 m IU/mL with a detection linearity interval of 11.25 to 360 m IU/mL (R ² = 0.9985). The double gE antigen sandwich ELISA showed a sensitivity of 95.08 % and specificity of 100 % compared to the fluorescent-antibody-to-membrane-antigen (FAMA) test, and it showed a sensitivity of 100 % and a specificity of 94.74 % compared to a commercial neutralizing antibody detection kit. Thus, the established double antigen sandwich ELISA can be used as a sensitive and specific quantitative method to evaluate immunity to VZV.

Flow Cytometry of Nonhematopoietic Neoplasms

Many epithelial neoplasms can be analyzed by flow cytometry (FC), particularly from serous cavity effusion samples, using EpCAM, a cell adhesion molecule expressed on most normal epithelial cells and expressed at a higher level in most epithelial neoplasms. A simple 3-color flow cytometric panel can provide a high sensitivity and specificity compared to cytomorphology. FC provides more rapid immunophenotyping than conventional immunohistochemical staining, can identify rare malignant cells that could be missed by a cytological exam alone, and can be utilized to evaluate limited samples such as cerebrospinal fluid or fine-needle aspiration samples. Flow cytometric analysis for epithelial antigens can be combined with DNA ploidy analysis or assessment of the nucleus-to-cytoplasm ratio. Panels of flow cytometric markers are useful for the assessment of pediatric nonhematopoietic neoplasms, including neuroblastomas, primitive neuroectodermal tumors, Wilms' tumor, rhabdomyosarcomas, germ cell tumors, and hemangiopericytomas, as well as small-round-blue-cell tumors in adults, including small-cell carcinomas.