Breast cancer risk is influenced by rare coding variants in susceptibility genes such as BRCA1 and many common, mainly non-coding variants. However, much of the genetic contribution to breast cancer risk remains unknown. We report results from a genome-wide association study (GWAS) of breast cancer in 122,977 cases and 105,974 controls of European ancestry and 14,068 cases and 13,104 controls of East Asian ancestry1. We identified 65 new loci associated with overall breast cancer at p<5x10-8. The majority of credible risk SNPs in the new loci fall in distal regulatory elements, and by integrating in-silico data to predict target genes in breast cells at each locus, we demonstrate a strong overlap between candidate target genes and somatic driver genes in breast tumours. We also find that heritability of breast cancer due to all SNPs in regulatory features was 2-5-fold enriched relative to the genome-wide average, with strong enrichment for particular transcription factor binding sites. These results provide further insight into genetic susceptibility to breast cancer and will improve the utility of genetic risk scores for individualized screening and prevention.

Tumor suppressor gene silencing through cytosine methylation contributes to cancer formation. Whether DNA demethylation enzymes counteract this oncogenic effect is unknown. Here, we show that TET1, a dioxygenase involved in cytosine demethylation, is downregulated in prostate and breast cancer tissues. TET1 depletion facilitates cell invasion, tumor growth, and cancer metastasis in prostate xenograft models and correlates with poor survival rates in breast cancer patients. Consistently, enforced expression of TET1 reduces cell invasion and breast xenograft tumor formation. Mechanistically, TET1 suppresses cell invasion through its dioxygenase and DNA binding activities. Furthermore, TET1 maintains the expression of tissue inhibitors of metalloproteinase (TIMP) family proteins 2 and 3 by inhibiting their DNA methylation. Concurrent low expression of TET1 and TIMP2 or TIMP3 correlates with advanced node status in clinical samples. Together, these results illustrate a mechanism by which TET1 suppresses tumor development and invasion partly through downregulation of critical gene methylation.

Adult intussusception is an unusual and challenging condition and is a preoperative diagnostic problem. We discuss our 20 years of experience in treatment strategies for dealing with such unusual problems.

Breast cancer is the most common cancer among women. To date, 22 common breast cancer susceptibility loci have been identified accounting for ~ 8% of the heritability of the disease. We followed up 72 promising associations from two independent Genome Wide Association Studies (GWAS) in ~70,000 cases and ~68,000 controls from 41 case-control studies and nine breast cancer GWAS. We identified three new breast cancer risk loci on 12p11 (rs10771399; P=2.7 × 10−35), 12q24 (rs1292011; P=4.3×10−19) and 21q21 (rs2823093; P=1.1×10−12). SNP rs10771399 was associated with similar relative risks for both estrogen receptor (ER)-negative and ER-positive breast cancer, whereas the other two loci were associated only with ER-positive disease. Two of the loci lie in regions that contain strong plausible candidate genes: PTHLH (12p11) plays a crucial role in mammary gland development and the establishment of bone metastasis in breast cancer, while NRIP1 (21q21) encodes an ER co-factor and has a role in the regulation of breast cancer cell growth.

Loss of heterozygosity (LOH) allows the expression of recessive mutation in tumor suppressor genes (TSG). Therefore, on the basis of Knudson's`two-hit' hypothesis for TSG inactivation, the detection of a high LOH frequency in a chromosomal region is considered critical for TSG localization. One of these LOH regions in breast cancer is 16q22.1, which has been suggested to re¯ect the involvement of E-cadherin (E-cad), a cell ± cell adhesion molecule. To con®rm the tumorigenic role of Ecad, 81 sporadic invasive ductal carcinomas (IDCs) of the breast were tested for the`two hits' required to inactivate this gene. A high frequency (37.3%) of LOH was detected in 67 informative tumors, but no mutation was found. To examine the possibility that transcriptional mechanisms serve as the second hit in tumors with LOH, speci®c pathways, including genetic variant and hypermethylation at the promoter region and abnormal expression of positive (WT1) and negative (Snail) transcription factors, were identi®ed. Of these, promoter hypermethylation and increased expression of Snail were found to be common (435%), and to be strongly associated with reduced/negative E-cad expression (P50.05). However, unexpectedly, a signi®cantly negative association was found between the existence of LOH and promoter hypermethylation (P50.05), which contradicts the`two-hit' model. Instead, since they coexisted in a high frequency of tumors, hypermethylation may work in concert with increased Snail to inactivate E-cad expression. Given that E-cad is involved in diverse mechanisms, loss of which is bene®cial for tumors to invade but may also trigger apoptosis, this study suggests that maintaining a reversible mechanism, either by controlling the gene at the transcriptional level or by retaining an intact allele subsequent to LOH, might be important for E-cad in IDC and may also be common in TSGs possessing diverse functions. These ®ndings provide clues to explain why certain TSGs identi®ed by LOH cannot ful®l the two-hit hypothesis. Oncogene (2001) 20, 3814 ± 3823.

Breast cancers demonstrate substantial biological, clinical and etiological heterogeneity. We investigated breast cancer risk associations of eight susceptibility loci identified in GWAS and two putative susceptibility loci in candidate genes in relation to specific breast tumor subtypes. Subtypes were defined by five markers (ER, PR, HER2, CK5/6, EGFR) and other pathological and clinical features. Analyses included up to 30 040 invasive breast cancer cases and 53 692 controls from 31 studies within the Breast Cancer Association Consortium. We confirmed previous reports of stronger associations with ER+ than ER- tumors for six of the eight loci identified in GWAS: rs2981582 (10q26) (P-heterogeneity = 6.1 × 10(-18)), rs3803662 (16q12) (P = 3.7 × 10(-5)), rs13281615 (8q24) (P = 0.002), rs13387042 (2q35) (P = 0.006), rs4973768 (3p24) (P = 0.003) and rs6504950 (17q23) (P = 0.002). The two candidate loci, CASP8 (rs1045485, rs17468277) and TGFB1 (rs1982073), were most strongly related with the risk of PR negative tumors (P = 5.1 × 10(-6) and P = 4.1 × 10(-4), respectively), as previously suggested. Four of the eight loci identified in GWAS were associated with triple negative tumors (P ≤ 0.016): rs3803662 (16q12), rs889312 (5q11), rs3817198 (11p15) and rs13387042 (2q35); however, only two of them (16q12 and 2q35) were associated with tumors with the core basal phenotype (P ≤ 0.002). These analyses are consistent with different biological origins of breast cancers, and indicate that tumor stratification might help in the identification and characterization of novel risk factors for breast cancer subtypes. This may eventually result in further improvements in prevention, early detection and treatment.

We examined the expression in breast cancer stem cells (BCSCs) of Globo H, a potential tumor-associated antigen for immunotherapy of epithelial cancers including breast cancer. Flow cytometry revealed Globo H expression in 25/41 breast cancer specimens (61.0%). Non-BCSCs from 25/25 and BCSCs from 8/40 (20%) expressed Globo H. We showed the expression of stage-specific embryonic antigen 3 (SSEA3), the pentasaccharide precursor of Globo H, in 31/40 (77.5%) tumors. Non-BCSCs from 29/31 and BCSCs from 25/40 (62.5%) expressed SSEA3. Like Globo H, SSEA3 expression in normal tissues was predominately at the secretory borders of epithelium, where access to the immune system is restricted. Immunization of mice with Globo H-KLH and α-GalCer induced antibodies reactive with Globo H and SSEA3, suggesting that a Globo H-based vaccine will target tumor cells expressing Globo H or SSEA3. We next sought to reduce Globo H expression by siRNA targeting fucosyltransferase ( FUT ) 1 and 2, which mediate alpha-1,2 linkage of fucose to SSEA3 to generate Globo H. We showed both genes to be involved in the biosynthesis of Globo H. Moreover, FUT2 expression in BCSCs was significantly lower than in non-BCSCs harvested from a primary human breast cancer in NOD/SCID mouse, whereas FUT1 was slightly lower in BCSCs. Thus, the lower expression of Globo H in BCSCs may be attributed to less FUT2/FUT1, and to reduced SSEA3 in BCSCs compared with non-BCSCs. Our findings provide insight into further development of a Globo H-based vaccine and FUT1/FUT2 -targeted therapy for breast cancer.

Cancer-associated carbohydrate antigens are often found on the surface of cancer cells. Understanding their roles in cancer progression will lead to the development of new therapeutics and high-sensitivity diagnostics for cancers. Globo H is a member of this family, which is highly expressed on breast cancer cells. Here, we report the development of a glycan microarray of Globo H and its analogs for measurement of the dissociation constants on surface (K D,surf) with three different monoclonal antibodies (VK-9, Mbr1, and anti-SSEA-3), to deduce their binding specificity. The glycan microarray was also used to detect the amount of antibodies present in the plasma of breast cancer patients and normal blood donors. It was shown that the amount of antibodies against Globo H from breast cancer patients were significantly higher than normal blood donors, providing a new tool for possible breast cancer diagnosis. Compared with the traditional ELISA method, this array method required only atto-mole amounts of materials and is more effective and more sensitive (5 orders of magnitude). The glycan microarray thus provides a new platform for use to monitor the immune response to carbohydrate epitopes after vaccine therapy or during the course of cancer progression.array ͉ diagnosis