Supplementary Figure 1, Tables 1-4 from A SNP in a let-7 microRNA Complementary Site in the KRAS 3′ Untranslated Region Increases Non–Small Cell Lung Cancer Risk

Supplementary Table 1 from A KRAS-Variant in Ovarian Cancer Acts as a Genetic Marker of Cancer Risk

Supplementary Figure 2 from A KRAS-Variant in Ovarian Cancer Acts as a Genetic Marker of Cancer Risk

Supplementary Tables 1-4 from The <i>let-7</i> MicroRNA Represses Cell Proliferation Pathways in Human Cells

Supplementary Materials, Figures 1-4 from The <i>let-7</i> MicroRNA Represses Cell Proliferation Pathways in Human Cells

While cancer is a serious health issue, there are very few genetic biomarkers that predict predisposition, prognosis, diagnosis, and treatment response. Recently, sequence variations that disrupt microRNA (miRNA)-mediated regulation of genes have been shown to be associated with many human diseases, including cancer. In an early example, a variant at one particular single nucleotide polymorphism (SNP) in a let-7 miRNA complementary site in the 3' untranslated region (3' UTR) of the KRAS gene was associated with risk and outcome of various cancers. The KRAS oncogene is an important regulator of cellular proliferation, and is frequently mutated in cancers. To discover additional sequence variants in the 3' UTR of KRAS with the potential as genetic biomarkers, we resequenced the complete region of the 3' UTR of KRAS in multiple non-small cell lung cancer and epithelial ovarian cancer cases either by Sanger sequencing or capture enrichment followed by high-throughput sequencing. Here we report a comprehensive list of sequence variations identified in cases, with some potentially dysregulating expression of KRAS by altering putative miRNA complementary sites. Notably, rs712, rs9266, and one novel variant may have a functional role in regulation of KRAS by disrupting complementary sites of various miRNAs, including let-7 and miR-181.

Although they were first discovered in C. elegans and their exact mechanism of action is still not understood, microRNAs (miRNAs) have captured the imagination of many scientists because of their involvement in human cancers. MiRNAs regulate important cancer genesby binding to sites in their 3′ UTRs, and many miRNAs are located in fragile regions of the human genome, segments of chromosomes that are often involved in deletions, amplifications and breakpoints associated with cancer. In addition, there is growing evidence that mis-expression or loss of miRNAs is sufficient to cause cancer. There is also increasing evidence that DNA variations in miRNA genes and inmiRNA binding sites are involved in cancer susceptibility.

Downlo rian cancer (OC) is the single most deadly form of women's cancer, typically presenting as an advanced e at diagnosis in part due to a lack of known risk factors or genetic markers of risk. The KRAS oncogene tered levels of the microRNA (miRNA) let-7 are associated with an increased risk of developing solid s. In this study, we investigated a hypothesized association between an increased risk of OC and a varlele of KRAS at rs61764370, referred to as the KRAS-variant, which disrupts a let-7 miRNA binding site in ncogene. Specimens obtained were tested for the presence of the KRAS-variant from nonselected OC ts in three independent cohorts, two independent ovarian case-control studies, and OC patients with tary breast and ovarian cancer syndrome (HBOC) as well as their family members. Our results indicate e KRAS-variant is associated with more than 25% of nonselected OC cases. Further, we found that it is a r for a significant increased risk of developing OC, as confirmed by two independent case-control analastly, we determined that the KRAS-variant was present in 61% of HBOC patients without BRCA1 or mutations, previously considered uninformative, as well as in their family members with cancer. Our gs strongly support the hypothesis that the KRAS-variant is a genetic marker for increased risk of defindin veloping OC, and they suggest that the KRAS-variant may be a new genetic marker of cancer risk for HBOC families without other known genetic abnormalities. Cancer Res; 70(16); 6509–15. ©2010 AACR.

Abstract Ovarian cancer (OC) is the single most deadly form of women's cancer, typically presenting as an advanced disease at diagnosis in part due to a lack of known risk factors or genetic markers of risk. The KRAS oncogene and altered levels of the microRNA (miRNA) let-7 are associated with an increased risk of developing solid tumors. In this study, we investigated a hypothesized association between an increased risk of OC and a variant allele of KRAS at rs61764370, referred to as the KRAS-variant, which disrupts a let-7 miRNA binding site in this oncogene. Specimens obtained were tested for the presence of the KRAS-variant from nonselected OC patients in three independent cohorts, two independent ovarian case-control studies, and OC patients with hereditary breast and ovarian cancer syndrome (HBOC) as well as their family members. Our results indicate that the KRAS-variant is associated with more than 25% of nonselected OC cases. Further, we found that it is a marker for a significant increased risk of developing OC, as confirmed by two independent case-control analyses. Lastly, we determined that the KRAS-variant was present in 61% of HBOC patients without BRCA1 or BRCA2 mutations, previously considered uninformative, as well as in their family members with cancer. Our findings strongly support the hypothesis that the KRAS-variant is a genetic marker for increased risk of developing OC, and they suggest that the KRAS-variant may be a new genetic marker of cancer risk for HBOC families without other known genetic abnormalities. Cancer Res; 70(16); 6509–15. ©2010 AACR.

Identification of biological markers of cancer is a major area of research. Biomarkers could identify the presence of a tumor before it could otherwise be easily detected, and the ability to detect cancers at early stages is a key factor in increasing survivability. For example, the American Cancer Society finds that a reason breast cancer survival rates are so high is that there are good methods for early detection of tumors. However, this is not the case for most cancers. For lung cancer, the five-year survival is 15%, but for the 16% of lung cancer cases diagnosed at early stages, the five-year survival rate is 49% 1. While this is just one example, the ability to identify a cancer while it is still localized is clearly beneficial. Currently, most methods for discovering and testing tumor biomarkers are difficult and labor-intensive procedures, and at most, only several markers can be tested for at one time. However, due to the simplicity of getting a blood sample, easily testable biomarkers found in blood serum would be especially useful.

Abstract Lung cancer is the leading cause of cancer deaths worldwide, yet few genetic markers of lung cancer risk useful for screening exist. The let-7 family-of-microRNAs (miRNA) are global genetic regulators important in controlling lung cancer oncogene expression by binding to the 3′ untranslated regions of their target mRNAs. The purpose of this study was to identify single nucleotide polymorphisms (SNP) that could modify let-7 binding and to assess the effect of such SNPs on target gene regulation and risk for non–small cell lung cancer (NSCLC). let-7 complementary sites (LCS) were sequenced in the KRAS 3′ untranslated region from 74 NSCLC cases to identify mutations and SNPs that correlated with NSCLC. The allele frequency of a previously unidentified SNP at LCS6 was characterized in 2,433 people (representing 46 human populations). The frequency of the variant allele is 18.1% to 20.3% in NSCLC patients and 5.8% in world populations. The association between the SNP and the risk for NSCLC was defined in two independent case-control studies. A case-control study of lung cancer from New Mexico showed a 2.3-fold increased risk (confidence interval, 1.1–4.6; P = 0.02) for NSCLC cancer in patients who smoked <40 pack-years. This association was validated in a second independent case-control study. Functionally, the variant allele results in KRAS overexpression in vitro. The LCS6 variant allele in a KRAS miRANA complementary site is significantly associated with increased risk for NSCLC among moderate smokers and represents a new paradigm for let-7 miRNAs in lung cancer susceptibility. [Cancer Res 2008;68(20):8535–40]

Abstract MicroRNAs play important roles in animal development, cell differentiation, and metabolism and have been implicated in human cancer. The let-7 microRNA controls the timing of cell cycle exit and terminal differentiation in Caenorhabditis elegans and is poorly expressed or deleted in human lung tumors. Here, we show that let-7 is highly expressed in normal lung tissue, and that inhibiting let-7 function leads to increased cell division in A549 lung cancer cells. Overexpression of let-7 in cancer cell lines alters cell cycle progression and reduces cell division, providing evidence that let-7 functions as a tumor suppressor in lung cells. let-7 was previously shown to regulate the expression of the RAS lung cancer oncogenes, and our work now shows that multiple genes involved in cell cycle and cell division functions are also directly or indirectly repressed by let-7. This work reveals the let-7 microRNA to be a master regulator of cell proliferation pathways. [Cancer Res 2007;67(16):7713–22]

Supplementary Tables 1-4 from The let-7 MicroRNA Represses Cell Proliferation Pathways in Human Cells