GNEN-1: a spontaneously immortalized cell line from gastric neuroendocrine neoplasia

Mixed neuroendocrine-non-neuroendocrine neoplasms (MINEN) are rare tumors that consist of at least 30% of both neuroendocrine and non-neuroendocrine components. The data concerning pathogenesis of MINEN suggest a monoclonal origin. We describe a spontaneously immortalized cell line derived from gastric MINEN called GNEN-1. Primary tumor consisted of components of high-grade euroendocrine carcinoma and adenocarcinoma. The GNEN-1 cell line was initiated from metastatic tumor cells of peritoneal fluid and expresses a purely neuroendocrine phenotype. The GNEN-1 cell line grows as monolayers and has retained the neuroendocrine phenotype with positivity for chromogranin A in immunohistochemistry. Electron microscopy showed cytoplasmic dense core granules and axon hillocks. The karyotype revealed alterations typical of both adenocarcinoma and neuroendocrine carcinoma such as trisomy 7 and 8. GNEN-1 cells were also positive for stanniocalcin-1, a marker of poor prognosis in gastric carcinomas. Expression of several markers related to neuroendocrine tumors was found. There have been only few studies on the pathogenesis of MINEN and management of the disease due to the rarity of this tumor type. Here we describe for the first time an immortalized cell line derived from fixed gastric NEN. The GNEN-1 line offers a tool for future research on gastric NEN.

Clinical Significance of Non-Invasive Prenatal Screening for Trisomy 7: Cohort Study and Literature Review

Trisomy 7 is the most frequently observed type of rare autosomal trisomies in genome-wide non-invasive prenatal screening (NIPS). Currently, the clinical significance of trisomy 7 NIPS-positive results is still unknown. We reviewed two independent cohorts from two laboratories where similar NIPS metrics were applied. A total of 70,441 singleton cases who underwent genome-wide NIPS were analyzed, among which 39 pregnancies were positive for trisomy 7, yielding a screen-positive rate of 0.055% (39/70,441). There were 28 cases with invasive testing results available; the positive predictive value (PPV) was 3.6% (1/28). We then searched the published NIPS studies to generate a large cohort of 437,873 pregnancies and identified 247 cases (0.056%) that were screened positive for trisomy 7. The overall PPV was 3.4% (4/118) in the combined data. The presence of uniparental disomy 7 was not detected in the NIPS trisomy 7-positive pregnancies with normal fetal karyotype. Among the 85 cases with pregnancy outcome available in combined data, 88.2% were normal live births, 14.1% had intrauterine growth restriction, preterm birth or low birth weight, 3.5% presented with ultrasound abnormality, and no fetal loss was observed. Our data provide valuable information for counseling and management of trisomy 7-positive NIPS pregnancies.

Clinical management of pregnancies with positive screening results for rare autosomal aneuploidies at a single center

Objective To review our experiences on clinical management of pregnancies with positive noninvasive prenatal testing (NIPT) results for rare autosomal aneuploidies (RAAs) at a single center. Methods We performed a retrospective study and reviewed data from 18,016 pregnancies undergoing NIPT at a single center in China from March 2017 to February 2020. Depending on the patient’s choice, women with positive screening results for RAAs underwent chromosomal microarray analysis for invasive prenatal diagnosis. Results Thirty-three positive cases for RAAs were identified, with a positive screening rate of 0.18%. The most common RAA was trisomy 7 (33.3%), while trisomies for other chromosomes were less frequent. Monosomies involving chromosomes 16, 14, and 22 were observed. Twenty-eight cases of RAAs underwent invasive diagnosis. Abnormal pregnancy outcomes were observed in four cases, including true fetal mosaicism (n=1), partial uniparental disomy (n=1), miscarriage (n=1), and structural anomalies on ultrasound (n=1). Conclusions RAAs at NIPT might be associated with fetal uniparental disomy, mosaic aneuploidy, and poor pregnancy outcomes, but most positive cases have normal pregnancy outcomes. For RAAs, genetic counseling on the potential risks of abnormal NIPT results, as well as on benefits and limitations of invasive prenatal diagnosis, might help guide clinical management.

FLUORESCENT IN SITU HYBRIDIZATION AND IMMUNOHISTOCHEMISTRY FOR SUBTYPING “NON-CLASSIFIABLE” RENAL CELL CARCINOMAS

Renal tumors account for about 3% of the malignancies in adults. Clear cell subtype renal cell carcinoma (RCC) and papillary RCC are the most common renal tubular epithelial carcinomas and their differentiation is important because they have a different prognosis and are associated with different treatment protocols. In most cases, histological features allow accurate diagnosis of renal cell carcinomas. There are also overlapping morphological findings between certain kidney neoplasms that make their subtyping extremely difficult. Some of them display papillary architecture but also have a clear cell component and it is not clear whether they should be classified as clear cell RCC or papillary RCC. In our study we performed an immunohistochemical and genetic analysis of 24 cases of RCC classified as non-classifiable with mixed papillary and clear cell components treated at Clinic of Urology in University Hospital "St. George "-Plovdiv. The mean age of patients was 54.5 years, and gender distribution: 60% male and 40% female. Based on the results of immunohistochemistry and fluorescence in situ hybridization (FISH), patients were stratified in 2 groups. The first group included 16 of the cases where strong immunoreactivity was found for alfa-methyl coenzyme A racemase (AMACR), with cytokeratin 7 (CK7) being present in 15 of these. In all cases in this group, FISH proved trisomy 7 and 17, in 4-9p deletion, and in 2- 3p deletion. The remaining 8 cases were stratified in the second group - all negative for CK7 and only one positive for AMACR. Genetic analysis showed a lack of trisomy 7 and 17 in all cases, as well as a deletion of 3p and 9p in 7 of them. The combination of immunohistochemical and genetic analyzes allows with a high accuracy to differentiate cases of papillary RCC from those with clear cell RCC.