CRISPR/Cas9 targeting of passenger single nucleotide variants in haploinsufficient or essential genes expands cancer therapy prospects.

CRISPR/Cas9 technology has effectively targeted cancer-specific oncogenic hotspot mutations or insertion-deletions. However, their limited prevalence in tumors restricts their application. We propose a novel approach targeting passenger single nucleotide variants (SNVs) in haploinsufficient or essential genes to broaden therapeutic options. By disrupting haploinsufficient or essential genes through the cleavage of DNA in the SNV region using CRISPR/Cas9, we achieved the selective elimination of cancer cells without affecting normal cells. We found that, on average, 44.8% of solid cancer patients are eligible for our approach, a substantial increase compared to the 14.4% of patients with CRISPR/Cas9-applicable oncogenic hotspot mutations. Through in vitro and in vivo experiments, we validated our strategy by targeting a passenger mutation in the essential ribosomal gene RRP9 and haploinsufficient gene SMG6. This demonstrates the potential of our strategy to selectively eliminate cancer cells and expand therapeutic opportunities.

Comparative Study on Two COVID-19 Outbreaks at a Long-Term Mental Health Facility in Korea in 2020 and 2022.

(1) Background and Objectives: There were two distinct coronavirus disease 2019 (COVID-19) outbreaks in 2020 and 2022 at a long-term mental health facility (LTMHF) in Gyeonggi Province, Korea. We aimed to compare the two outbreaks and identify differences in epidemiological and clinical outcomes due to changes in epidemic timing and management methods. (2) Materials and Methods: The structural, operational, and case-specific LTMHF data of COVID-19-confirmed patients during these outbreaks in 2020 and 2022 were retrospectively analyzed. (3) Results: Forty individuals (37 residents) in 2020 and thirty-nine (32 residents) in 2022 were confirmed to have COVID-19, and ten were infected twice. Facility isolation was implemented as an infection control measure, and one COVID-19-related death occurred in 2020. All residents and staff were vaccinated at least twice in 2022; moreover, in 2022, 38 patients (97.4%) received a third vaccination less than months before infection. The average Ct value of the cases in 2022 was significantly higher than that in 2020; however, vaccine-breakthrough (V-BT) and reinfection after vaccination rates were similar. (4) Conclusions: COVID-19 vaccination could help lower the viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was inversely correlated with Ct values, and ventilation system improvements in health facilities might reduce transmissibility.

Viral shedding patterns of symptomatic SARS-CoV-2 infections by periods of variant predominance and vaccination status in Gyeonggi Province, Korea.

OBJECTIVES: We compared the viral cycle threshold (Ct) values of infected patients to better understand viral kinetics by vaccination status during different periods of variant predominance in Gyeonggi Province, Korea. METHODS: We obtained case-specific data from the coronavirus disease 2019 (COVID-19) surveillance system, Gyeonggi in-depth epidemiological report system, and Health Insurance Review & Assessment Service from January 2020 to January 2022. We defined periods of variant predominance and explored Ct values by analyzing viral sequencing test results. Using a generalized additive model, we performed a nonlinear regression analysis to determine viral kinetics over time. RESULTS: Cases in the Delta variant's period of predominance had higher viral shedding patterns than cases in other periods. The temporal change of viral shedding did not vary by vaccination status in the Omicron-predominant period, but viral shedding decreased in patients who had completed their third vaccination in the Delta-predominant period. During the Delta-predominant and Omicron-predominant periods, the time from symptom onset to peak viral shedding based on the E gene was approximately 2.4 days (95% confidence interval [CI], 2.2 to 2.5) and 2.1 days (95% CI, 2.0 to 2.1), respectively. CONCLUSIONS: In one-time tests conducted to diagnose COVID-19 in a large population, although no adjustment for individual characteristics was conducted, it was confirmed that viral shedding differed by the predominant strain and vaccination history. These results show the value of utilizing hundreds of thousands of test data produced at COVID-19 screening test centers.

Experience of a COVID-19 outbreak response in a general hospital in Gyeonggi Province, Korea.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) outbreaks in general hospitals are particularly risky because they not only overburden the regional healthcare delivery system, but also increase the possibility of community transmission. This study shares an experience of a COVID-19 outbreak response in a general hospital in Gyeonggi Province, Korea. METHODS: Since the first COVID-19 confirmed case was recognized in Hospital A on March 29, 2020, the Immediate Response Team of Gyeonggi Province and Korea Disease Control and Prevention Agency devised a plan to conduct an epidemiological investigation and minimize the paralysis of hospital functions. Apart from the epidemiological investigation, a risk assessment of the hospital and management of contacts, including patients and workers, were also undertaken. RESULTS: In total, 72 confirmed cases were identified, including 26 hospitalized patients, 16 healthcare personnel, 7 visitors, and 22 cases identified externally. The majority of the confirmed cases were exposed in Ward B or were contacts of people exposed in Ward A (58.3% of 72 cases). Among healthcare personnel, caregivers were found to be the most vulnerable to COVID-19 in this outbreak. CONCLUSIONS: Preparation for all possible situations in medical facilities is important because it is difficult to find alternative resources. The findings of this study provide information on controlling the further transmission of COVID-19 and furnish evidence of the importance of ordinary management skills to be prepared for COVID-19.

Early Intervention Reduces the Spread of COVID-19 in Long-Term Care Facilities in the Republic of Korea.

This study describes the epidemiological characteristics of coronavirus disease 2019 (COVID-19) based on reported cases from long-term care facilities. As of April 20th, 2020, 3 long-term care facilities in a metropolitan area of South Korea had reported cases of COVID-19. These facilities' employees were presumed to be the sources of infection. There were 2 nursing hospitals that did not report any additional cases. One nursing home had a total of 25 cases, with an attack rate of 51.4% (95% CI 35.6-67.0), and a fatality rate of 38.9% (95% CI 20.3-61.4) among residents. The results from this study suggest that early detection and maintenance of infection control minimizes the risk of rapid transmission.

CD99 Is Strongly Expressed in Basal Cells of the Normal Adult Epidermis and Some Subpopulations of Appendages: Comparison with Developing Fetal Skin.

BACKGROUND: CD99 is a cell surface transmembrane glycoprotein expressed in various tissues. CD99 is differentially expressed between subpopulations of each tissue and is highly expressed in certain hematopoietic and precursor cells. However, there has been no comprehensive study of CD99 expression in normal skin. We evaluated CD99 expression in normal human skin and developing fetal skin. METHODS: Seventy-five adult skin samples containing normal skin and eight fetal skin samples of different gestational ages were collected. CD99 immunohistochemical staining was performed to evaluate expression pattern in adult and fetal skin samples. CD99 and CD34 expression were compared by double immunofluorescence. RESULTS: In normal adult skin, CD99 was strongly expressed in the membrane of epidermal basal keratinocytes, hair follicle bulges and outer root sheaths, and inner secretory cells of eccrine sweat glands. In fetal skin, CD99 was not expressed on the periderm at 16 weeks of gestation but was expressed in basal cells of fetal skin at around 19 weeks of gestation. CD99 expression became comparable to that of the adult skin after 20 weeks of gestation. CD99 and CD34 were co-expressed in hair follicle outer root sheaths, as seen by double immunofluorescence study. CONCLUSIONS: This is the first study examining CD99 expression pattern in normal adult and fetal skin. CD99 tends to be expressed in the basal/precursor cells of epidermis and in hair follicles. These results provide a basis for future investigation on functions of CD99 in the skin and provide a novel potential target for the treatment of dermatologic lesions.

Pure primary squamous cell carcinoma of the ovary: a report of two cases and review of the literature.

Pure primary squamous cell carcinoma (SCCa) of the ovary not associated with pre-existing ovarian lesions including dermoid cysts, Brenner tumors, or endometriosis is extremely rare. The last 2 types of SCCa and pure primary SCCa have been classified by the World Health Organization criteria as surface epithelial-stromal tumors. On account of the rarity of pure primary SCCa of the ovary, the clinical features and effective treatments have not been established. This study describes 2 such cases that we recently encountered in a review of the literature. The literature shows that patients with advanced-stage tumors have very poor survival outcomes, despite a combination of surgery, radiation therapy, and chemotherapy.

A case of primary paraganglioma that arose in the pancreas: the Color Doppler ultrasonography and dynamic CT features.

Paragangliomas rarely originate from the pancreas and they are characterized on imaging studies as well-marginated, hypervascular masses with cystic areas. We herein report on a case report of pancreatic paraganglioma in a 57-year-old woman, which was confirmed on pathology. Color Doppler ultrasonography and dynamic CT demonstrated a well-demarcated, extremely hypervascular mass with prominent intratumoral vessels and early contrast filling of the draining veins from the mass. Endoscopic retrograde cholangiopancreatography showed that the main pancreatic duct was displaced and mildly dilated.

Clear cell adenocarcinoma arising in endometriosis of a previous episiotomy site.

BACKGROUND: Malignant transformation of endometriosis in an episiotomy site is rare. CASE: A 42-year-old woman presented with a palpable mass, 2.5 cm in size, just inside the posterior commissure of the vagina, at the site of a previous episiotomy for a vaginal delivery. Three years previously, an endometriotic cyst had been excised at the same site, and the patient had been treated with a gonadotropin-releasing hormone analogue for 6 months. Biopsy revealed a clear cell adenocarcinoma arising in endometriosis. The patient underwent radical surgery alone without adjuvant therapy. At 10-month follow-up, there was no evidence of recurrence. CONCLUSION: Patients who experience a recurrence of extragonadal endometriosis after prior therapy should be monitored carefully for malignant degeneration.

Radical surgical resection for carcinoid tumors of the ampulla.

Ampullary carcinoid tumors are extremely rare. The present study describes the clinicopathological features and outcomes for 10 ampullary carcinoid patients who underwent radical resection from 1998 to 2005. During this study period, 294 patients underwent pancreatoduodenectomy for ampullary neoplasms in our institution. The mean patient age was 58.0 +/- 13.4 years, and seven were male. Initial clinical manifestations were jaundice in four patients, nonspecific gastrointestinal symptoms in five, and completely asymptomatic in one. Standard pancreatoduodenectomy was performed in three patients, and pylorus-preserving pancreatoduodenectomy in seven, and there were no major complications. The mean tumor size and volume were 2.1 +/- 1.3 cm and 4.1 +/- 6.9 ml, respectively. Synaptophysin staining was positive in ten patients and chromogranin staining positive in eight. R0 resection was achieved in all ten patients. Overall and disease-free survival rates were 90 and 80% at 1 year, and 64 and 56% at 3 years, respectively. The liver was the most common site of initial metastasis after curative resection. Univariate analyses revealed that a maximal tumor diameter > or =2 cm and tumor extension beyond the ampulla were risk factors for tumor recurrence. In conclusion, while the majority of ampullary carcinoids are indolent, this tumor is associated with a relatively poor prognosis. We believe that radical resection, with the aim of complete tumor removal and cure, is the treatment of choice.

Prognostic impact of sarcomatous change of hepatocellular carcinoma in patients undergoing liver resection and liver transplantation.

Sarcomatous change has been rarely observed in hepatocellular carcinoma (HCC), but it is usually associated with very aggressive tumor behavior and widespread metastasis. To assess the impact of sarcomatous changes, we analyzed the outcomes of 15 patients with sarcomatous HCC after resection (n = 11) or liver transplantation (LT) (n = 4). No imaging findings characteristic of sarcomatous changes were observed. According to modified pathological tumor-node metastasis staging, the HCC lesions were classified as stage II in five patients, stage III in six, stage IVa2 in two, and stage IVb in one. The Milan criteria were met in 7 of 15 patients, including 3 of 4 in the LT group. R0 resection was achieved in 9 of 11 resected patients, and their 3-year overall and disease-free survival rates were both 18.2%. In the LT group, 3-year overall and disease-free survival rates were 37.5 and 25%, respectively. In patients within the Milan criteria, 2-year overall survival rate was 25% after resection and 33% after LT, showing no prognostic difference. Extrahepatic metastasis as initial recurrence was detected in 80% after resection and 66.7% after LT. In conclusion, we found that the prognosis of patients with sarcomatous HCC was very unfavorable after either resection or LT and that, except for liver biopsy, no diagnostic method could distinguish between sarcomatous and ordinary HCC. Vigorous postoperative systemic surveillance may be helpful for timely detection and treatment of localized metastases.

Pituitary carcinoma with mandibular metastasis: a case report.

Pituitary carcinomas are rare primary adenohypophyseal tumors with cerebrospinal or extracranial metastasis. The present case, the first report of the disease in Korea, involved a 36-yr-old woman who presented with a 3-week history of headache. Brain magnetic resonance imaging revealed a 2.5-cm sellar and suprasellar mass showing heterogeneous enhancement with suspicious invasion of both cavernous sinuses. The patient underwent gross-total resection. The tumor cells were composed of polygonal cells singly or in variable-sized nests. The nuclei were large and round with prominent nucleoli. The cytoplasms was acidophilic and granular. Marked pleomorphism and frequent mitoses (3 per 10 HPFs) were found. By immunohistochemistry, tumor cells were strongly positive for prolactin, but negative for ACTH and GH. Additional immunostainings for cytokeratin, vimentin, and glial fibrillary acidic protein (GFAP) were negative. After the surgery, the patient received radiotherapy because of the atypical histologic features. The prolactin level fell from 123.17 ng/mL to 5.17 ng/mL after surgery. Nine months after the initial diagnosis, the patient died from mandibular metastasis associated with the pituitary carcinoma.

Primitive neuroectodermal tumor of the gallbladder.

Ewing sarcoma/primitive neuroectodermal tumor (ES/ PNET) most commonly occurs in the soft tissues of the extremities and the paravertebral areas. To our knowledge, no case of PNET has been reported in the gallbladder to date. We report a case of PNET of the gallbladder occurring in a 53-year-old woman. Microscopically, the monotonous small round cells with a formation of Homer-Wright rosettes showed intense membranous positive immunoreactivity for MIC2/CD99, as well as for neuron-specific enolase and synaptophysin. Other small round cell tumors, such as lymphoma, rhabdomyosarcoma, or melanoma, were excluded in light of negative immunoreactivity for leukocyte common antigen, desmin, and S100. The diagnosis of PNET was rendered based on the characteristic morphology and immunohistochemical findings, despite an absence of chromosomal translocations, such as t(11; 22)(q24;q12) and t(21;22)(q22;q12).