Browsing by Subject "Microsatellite instability"

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    Clinicopathologic and molecular characteristics of neuroendocrine carcinomas of the gallbladder
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Tang, Hui; Jiang, Xiaojun; Zhu, Lili; Xu, Liming; Wang, Xiaoxi; Li, Hong; Gao, Feifei; Liu, Xinxin; Ren, Chuanli; Zhao, Yan
    Gallbladder neuroendocrine carcinomas (GB-NECs) are a rare subtype of malignant gallbladder cancer (GBC). The genetic and molecular characteristics of GB-NECs are rarely reported. This study aims to assess the frequency of microsatellite instability (MSI) in GB-NECs and characterize their clinicopathologic and molecular features in comparison with gallbladder adenocarcinomas (GB-ADCs). Data from six patients with primary GB-NECs and 13 with GB-ADCs were collected and reevaluated. MSI assay, immunohisto-chemistry for mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2), comprehensive genomic profiling (CGP) via next-generation sequencing (NGS), and evaluation of tumor mutation burden (TMB) were conducted on these samples. The six GB-NEC cases were all female, with a mean age of 62.0±9.2 years. Of these, two cases were diagnosed as large cell neuroendocrine carcinomas (LCNECs), while the remaining four were small cell neuroendocrine carcinomas (SCNECs). Microsatellite states observed in both GB-NECs and GB-ADCs were consistently microsatellite stable (MSS). Notably, TP53 (100%, 6/6) and RB1 (100%, 6/6) exhibited the highest mutation frequency in GB-NECs, followed by SMAD4 (50%, 3/6), GNAS (50%, 3/6), and RICTOR (33%, 2/6), with RB1, GNAS, and RICTOR specifically present in GB-NECs. Immunohistochemical (IHC) assays of p53 and Rb in the six GB-NECs were highly consistent with genetic mutations detected by targeted NGS. Moreover, no statistical difference was observed in TMB between GB-NECs and GB-ADCs (p=0.864). Although overall survival in GB-NEC patients tended to be worse than in GB-ADC patients, this difference did not reach statistical significance (p=0.119). This study has identified the microsatellite states and molecular mutation features of GB-NECs, suggesting that co-mutations in TP53 and RB1 may signify a neuroendocrine inclination in GB-NECs. The IHC assay provides an effective complement to targeted NGS for determining the functional status of p53 and Rb in clinical practice.
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    Clinicopathological and molecular features of genome-stable colorectal cancers
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Jin, Lingyan; Jin, Hye Yeong; Kim, Younghoon; Cho, Nam Yun; Bae, Jeong Mo; Kim, Jung Ho; Han, Sae Won; Kim, TaeYou; Kang, Gyeong Hoon
    Colorectal cancers (CRCs) are traditionally divided into those with either chromosomal instability (CIN) or microsatellite instability (MSI). By utilizing TCGA data, the Laird team found a subset of CRCs, namely, genome-stable CRCs (GS CRCs), which lack both CIN and MSI. Although the molecular features of GS CRCs have been described in detail, the clinicopathological features are not well defined. A total of 437 CRCs were analyzed for copy number variation (CNV) statuses in eight genes (ARID1A, EGFR, FGFR1, KDM5B, MYBL2, MYC, SALL4, and SETDB1) using droplet-digital PCR. CRCs that showed CNV in ≤ one gene and no MSI were defined as GS-like CRCs. Clinicopathological and molecular features of GS-like CRCs were compared with those of CIN-like CRCs. GS-like CRCs comprised 4.6% of CRCs and showed a predilection toward the proximal colon, lower nuclear optical density, KRAS mutation, PIK3CA mutation, and aberrant expression of KRT7. Survival analysis showed no significant difference between the three subgroups. Through our study, the GS-like subtype was found to comprise a minor proportion of CRCs and have proclivity toward a proximal bowel location, hypochromatic tumor nuclei, aberrant KRT7 expression, and a high frequency of KRAS and PIK3CA mutations.