Cancer Genetics and Epigenetics 2018, Vol.6, No.4, 25-32
25
Research Article Open Access
The Progress of IGF2 in Breast Cancer Research
Min Yang
1
, Wenqian Li
1
, Dongwei Zhang
1, 2
1 Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
2 Heilongjiang Academy of Medical Sciences, Harbin, Heilongjiang, China
Corresponding author email
Cancer Genetics and Epigenetics, 2018, Vol.6, No.4 doi
Received: 03 Sep., 2018
Accepted: 08 Oct., 2018
Published: 26 Oct., 2018
Copyright © 2018
Yang et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Yang M., Li W.Q., and Zhang D.W., 2018, The progress of IGF2 in breast cancer research, Cancer Genetics and Epigenetics, 6(4): 25-32 (doi:
Abstract
Breast cancer is the first malignant tumor in Chinese women, which seriously threatens the health of the patients. The
research on breast cancer-related genes and therapeutic targets has been a hot topic in the research field. Insulin-like growth factor 2
(IGF2 insulin-like growth factor 2), with the development of precision medicine, the treatment of breast cancer tends to be more and
more individualized with the development of various malignant tumors, Association of IGF2 gene with invasiveness, risk if breast
cancer, progression rate and prognostic therapy, the author summarized the important achievements of IGF2 gene in the study of
breast cancer, including the structure and function of IGF2 gene, the cloning and expression of IGF2 gene, and the relationship
between IGF2 gene and breast cancer, etc.
Keywords
IGF2; Breast cancer; Gene expression; Methylation
Background
Breast cancer ranks first among female cancer incidence. In recent years, the incidence of breast cancer in China
has been rising rapidly, exceeding the world average growth level (2%), and the growth rate of big cities such as
Beijing and Shanghai has even reached about 5%. Breast cancer has become the most common malignant tumor
in women in China, with 269,000 new cases of breast cancer and 70,000 deaths each year. Insulin-like growth
factor 2 (IGF2) was cloned from an adult DNA library by Bell et al. (1984). IGF2 is a protein hormone that
regulates cell proliferation, growth, migration, differentiation and survival (Bergman et al., 2013; Coto et al.,
2018). IGF2 is preferentially expressed in many somatic cells during early embryonic and embryonic
development. At present, IGF2 can be detected in circulating plasma, and its detection rate in fetal circulating
blood is the highest. IGF2 is also an imprinted gene, expressing a paternal allele. But it is a double allele
expression in adult liver and central nervous system (Tahara et al., 2017). This article reviews the structure,
mechanism, imprinting status of IGF2 gene and its relationship with breast cancer.
1 IGF2 Gene Family, Structure and Function
1.1 IGF2 gene structure
IGF2 gene is a polypeptide composed of 67 amino acids (Figure 1), produced by hepatocytes and closely related
to insulin. IGF2 gene is located on chromosome 11p15.5 next to insulin gene, spanning 30 KB (Ben-Zaken et al.,
2017). IGF2 gene initially synthesized IGF2 protein precursor, which was composed of A-E domain and a
24-residue signal peptide. Signal fetal cleavage is a large number of IGF2 precursors. After translation,
O-glycosylation of residue E domain is carried out, which can promote the further processing of precursors. The
precursor of IGF2 loses E domain through continuous protein hydrolysis and becomes mature IGF2. Incomplete
treatment of IGF2 precursors leads to the inclusion of all or part of the E domain in the polypeptide, collectively
known as the large IGF2 gene, which secretes into the blood, accounting for 10-20% of the normal IGF2 gene.
Glycosylation of large IGF2 gene promotes the formation of ternary complexes in serum. Large IGF2 gene can
also promote the formation of binary complexes IGFBP2, IGFBP5 and IGFBP3. IGF2 gene transcription depends
on the four promoters of P1-4. During embryonic development, the expression and transcription of single allele
comes from P2-P4. In adult liver, there is expression of P1 promoter (Callum, 2013). In the process of growth and
