Introduction
Cancer is the second most common cause of death worldwide. Cancer was
responsible for 8.8 million deaths in 2015. Almost 70% of
cancer-related deaths occur in low- and middle-income countries
(Siegel et al., 2015). Several lifestyle
risk factors, including high body mass index, low fruit and vegetable
intake, lack of physical activity, and tobacco and alcohol consumption,
account for nearly one-third of deaths from cancer
(Forouzanfar et al., 2016,
Hoseini et al., 2014). The economic
impact of cancer is substantial and increasing
(McGuire, 2016).
Various factors, including environmental and genetic factors, are among
the most common ones that contribute to cancer development. However, the
mechanisms underlying cancer pathogenesis remain largely unclear. Long
non-coding RNAs (lncRNAs) have been widely investigated among the
potential genetic factors. It has been proposed that they play a crucial
role in cancer progression, tumorigenesis, and the biological activity
of malignant tumors (Kong et al., 2014,
Hu et al., 2015,
Hosseini et al., 2022). These
single-stranded, non-coding RNAs are among the significant regulators of
gene expression, including oncogenes and tumor suppressor genes, cell
cycle, proliferation, differentiation, and apoptosis
(Bartonicek et al., 2016,
Zhang et al., 2016,
Chen et al., 2012,
Bhan and Mandal, 2014).
To date, several lncRNAs have been discovered in the human genome
(Brosnan and Voinnet, 2009,
Rashidmayvan et al., 2022). Genetic
variants, specifically the single nucleotide polymorphisms (SNPs),
located in lncRNA genes have the potential to make a crucial impact on
lncRNA expression levels, processing, or on the secondary structure of
lncRNAs which results in cancer development and progression as well as
the alteration of drug responses (Cheetham
et al., 2013, Ling et al., 2015,
Pan et al., 2016). Dysregulation in
lncRNAs expression profile has been demonstrated by high throughput
analysis in many tumor cells (Gupta et
al., 2010, Schmidt et al., 2011,
Yang et al., 2012). The lncRNA growth
arrest-special 5 (GAS5 ) is a critical tumor suppressor lncRNA in
many types of human cancers, located on chromosome 1q25.
A large body of evidence has shown that GAS5 is down-regulated in
multiple cancers, including breast cancer, osteosarcoma, colorectal
cancer, bladder cancer, prostate cancer, pancreatic cancer, lung cancer,
gastric cancer, glioma, hepatocellular carcinoma, cervical cancer and
pleural mesothelioma (Zheng et al., 2016,
Li et al., 2017,
Li et al., 2018c,
Guo et al., 2017). Several investigations
have shown that GAS5 has the potential to act as a biomarker for
metastasis, prognosis, and cancer susceptibility
(Sun et al., 2014,
Kong et al., 2016,
Tu et al., 2014). Previous studies have
considered the possible association of lncRNA GAS5 rs145204276
polymorphism with cancer risk. It has been shown that this novel indel
(insertion /deletion) polymorphism in the promoter of lncRNA GAS5could modulate colorectal cancer risk through GAS5 expression
(Kong et al., 2016). However, there are
some inconsistencies in the results among different studies
(Li et al., 2018c,
Li et al., 2017,
Tao et al., 2015,
Xu et al., 2018,
Yuan et al., 2018,
Zheng et al., 2016,
Zhu et al., 2017,
Zhu et al., 2016,
Tang et al., 2019). Hence, we conducted a
meta-analysis including recent eligible studies to evaluate the
association of lncRNA GAS5 rs145204276 polymorphism and cancer risk.