eprintid: 37095
rev_number: 13
eprint_status: archive
userid: 9214
dir: disk0/00/03/70/95
datestamp: 2025-09-11 12:25:56
lastmod: 2025-09-26 11:38:34
status_changed: 2025-09-11 12:25:56
type: doctoralThesis
metadata_visibility: show
creators_name: Blandino, Alice
title: Identification and validation of circulating small non-coding RNAs associated with gallbladder cancer risk
subjects: ddc-610
divisions: i-911800
adv_faculty: af-05
cterms_swd: non-coding RNAs
cterms_swd: gallbladder cancer
cterms_swd: circulating biomarkers
abstract: This thesis focuses on the identification of circulating non-coding RNAs associated with the
 risk of developing gallbladder cancer, an aggressive disease with poor prognosis. Globally,
 gallbladder cancer exhibits high prevalence and mortality rates in specific geographic regions,
 such as Latin America, while remaining relatively rare in Europe. The molecular and genetic
 mechanisms underlying gallbladder cancer development have been partially explored, yet the
 precise contributions of specific biomarkers to its development remain inadequately under
stood. Non-coding RNAs play a central role in regulating abnormal cell processes, and hold
 promise as valuable biomarkers of early disease detection. Two different types of non-coding
 RNAs were investigated in this thesis: long non-coding RNAs and microRNAs. Long non
coding RNA expression levels were evaluated in the Chilean population, while microRNA
 regulation was investigated in individuals of European ancestry. Both studies relied on the
 combination of tissue and serum non-coding RNA expression data. The first study integrated three datasets containing long non-coding RNA expression data
 alone (gallstone n = 31, dysplasia n = 35, gallbladder cancer n = 32), both long non-coding
 RNAexpression and genotype data (controls n = 110), and genotype information exclusively
 (controls n = 2397, gallbladder cancer cases n = 540). On the first dataset, differentially
 expressed long non-coding RNAs along the progression from gallstones, to dysplasia and
 gallbladder cancer were preselected. In the second dataset, the associations between genetic
 variants (SNPs) and the serum expressions of the preselected long non-coding RNAs were  assessed, and the best models for prediction were selected. Finally, serum long non-coding
 RNA expressions were predicted based on individual genotypes, and the association with
 gallbladder cancer risk was estimated. AC084082.3 and LINC00662 exhibited increased ex
pression levels (p-value = 0.009), while C22orf34 showed downregulation in progressing from
 gallstones to gallbladder cancer (p-value = 0.04). Two SNPs were identified and validated
 for LINC00662 (r2 = 0.26) and three for C22orf34 (r2 = 0.24). Only the predicted serum
 expression of LINC00662 was significantly associated with gallbladder cancer risk, and linked
 to a 25% higher risk of developing cancer (odds ratio = 1.25, p-value = 0.02).
 In the second study, a three-step approach was applied to preselect microRNAs from German
 formalin-fixed paraffin-embedded tissue samples (gallstone n = 8, gallbladder cancer n = 40),
 screen microRNA expressions in serum prospective samples from three European cohorts (n
 = 37 gallbladder cancer case-control pairs), and validate the identified microRNAs in serum
 samples from three additional prospective cohorts (controls n = 36, gallbladder cancer cases
 n = 31). Statistical analyses also included pathway and meta-analysis, and examination of
 expression correlation between microRNAs and target genes. miR-4533 and miR-671-5p were
 overexpressed both in gallbladder cancer tissue and in the first set of serum samples. However,
 only the overexpression of miR-4533 was validated both in the second set of prospective serum
 samples, and through meta-analysis (p-value = 4.1x10−4). miR-4533 was mostly upregulated
 in individuals under 63.5 years, and with a body-mass index below 26.2 kg/m2. Pathway and
 correlation analyses revealed that miR-4533 targets SIPA1L2 in the Rap1 signaling pathway.
 This thesis demonstrates the heterogeneous nature of gallbladder cancer molecular profiles.
 Results from the first study suggest that preselection of long non-coding RNAs based on
 tissue samples and exploitation of related genetic variants facilitates the identification of cir
culating long non-coding RNAs linked to cancer risk. The second study draws attention to
 the importance of integrating tissue and serum biomarkers for the preselection, screening and
 validation of differentially expressed microRNAs. Both studies highlight the need for inter
national research collaborations to identify and validate biomarkers for secondary prevention
 of rare tumours such as gallbladder cancer. These results need to be validated and further
 refined in future studies, also with regard to their transferability to other sample types and
 populations.
date: 2025
id_scheme: DOI
id_number: 10.11588/heidok.00037095
ppn_swb: 1935997092
own_urn: urn:nbn:de:bsz:16-heidok-370954
date_accepted: 2025-07-14
advisor: HASH(0x559113634d60)
language: eng
bibsort: BLANDINOALIDENTIFICA20250805
full_text_status: public
place_of_pub: Heidelberg
citation:   Blandino, Alice  (2025) Identification and validation of circulating small non-coding RNAs associated with gallbladder cancer risk.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/37095/1/Dissertation_2024_AB_webversion.pdf