HSD17B1 genetic variants and hormone receptor-defined breast cancer

High expression of the RET receptor tyrosine kinase and its ligand GDNF identifies a high-risk subset of estrogen receptor positive breast cancer

PURPOSE

Resistance to endocrine therapy is the primary cause of treatment failure and death in patients with ER-positive (ER +)/luminal breast cancer. Expression and activation of the RET receptor tyrosine kinase may be driving poor outcomes. We aim to identify high-risk patients and druggable pathways for biomarker-based clinical trials.

METHODS

We obtained batch-normalized mRNA expression data from Breast Invasive Carcinoma-The Cancer Genome Atlas, PanCancer Atlas (BRCA-TCGA). To determine clinically significant cutoffs for RET expression, patients were grouped at different thresholds for Kaplan-Meier plotting. Differential gene expression (DGE) analysis and enrichment for gene sets was performed. transcriptomic dataset of antiestrogen-treated ER + tumors stratified by clinical response was then analyzed.

RESULTS

High RET expression was associated with worse outcomes in patients with ER + tumors, and stratification was enhanced by incorporating GDNF expression. High RET/GDNF patients had significantly lower overall survival (HR = 2.04, p = 0.012), progression-free survival (HR = 2.87, p < 0.001), disease-free survival (HR = 2.67, p < 0.001), and disease-specific survival (HR = 3.53, p < 0.001) than all other ER + patients. High RET/GDNF tumors were enriched for estrogen-independent signaling and targetable pathways including NTRK, PI3K, and KRAS. Tumors with adaptive resistance to endocrine therapy were enriched for gene expression signatures of high RET/GDNF primary tumors.

CONCLUSION

Expression and activation of the RET receptor tyrosine kinase may be driving poor outcomes in some patients with ER + breast cancer. ER + patients above the 75th percentile may benefit from clinical trials with tyrosine kinase inhibitors.

Role of hydroxysteroid (17beta) dehydrogenase type 1 in reproductive tissues and hormone-dependent diseases

Abnormal synthesis and metabolism of sex steroids is involved in the pathogenesis of various human diseases, such as endometriosis and cancers arising from the breast and uterus. Steroid biosynthesis is a multistep enzymatic process proceeding from cholesterol to highly active sex steroids via different intermediates. Human Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) enzyme shows a high capacity to produce the highly active estrogen, estradiol, from a precursor hormone, estrone. However, the enzyme may also play a role in other steps of the steroid biosynthesis pathway. In this article, we have reviewed the literature on HSD17B1, and summarize the role of the enzyme in hormone-dependent diseases in women as evidenced by preclinical studies.

Polymorphisms in Estrogen Synthesis Genes and Symptom Clusters During the Menopausal Transition and Early Postmenopause: Observations From the Seattle Midlife Women's Health Study

During the menopausal transition and early postmenopause, participants in the Seattle Midlife Women's Health Study (SMWHS) experienced one of the three symptom severity clusters identified through latent class analysis: severe hot flashes with moderate sleep, mood, cognitive, and pain symptoms (high-severity hot flash); low-severity hot flashes with moderate levels of all other symptom groups (moderate severity); and low levels of all symptom groups (low severity). In an effort to determine whether gene polymorphisms were associated with these symptom severity classes, we tested associations between gene polymorphisms in the estrogen synthesis pathways (cytochrome P450 19 [CYP 19] and 17 beta hydroxysteroid dehydrogenase [ 17HSDB1]) and the three symptom severity clusters. SMWHS participants ( N = 137) recorded symptoms monthly in diaries and provided buccal smears for genotyping. Multilevel latent class analysis with multinomial regression was used to determine associations between gene polymorphisms and symptom severity clusters. Only the 17HSDB1 polymorphisms ( rs615942 and rs592389) were associated significantly with the high-severity hot flash cluster versus the low-severity symptom cluster. None of the polymorphisms was associated with the moderate-severity cluster versus the low-severity symptom cluster. Findings of associations of the 17HSDB1 polymorphisms with the high-severity hot flash symptom cluster are consistent with those of an association between 17HSDB1 polymorphisms and hot flashes in the Study of Women and Health Across the Nation population and our previous findings of associations between these polymorphisms with greater estrone levels.

Polymorphism of HSD17B1 Ser312Gly with Cancer Risk: Evidence from 66,147 Subjects

Hydroxysteroid (17-beta)dehydrogenase 1(HSD17B1) plays a central role in sex steroid hormone metabolism. HSD17B1 polymorphic variants may contribute to cancer susceptibility. Numerous investigations have been conducted to assess the association between HSD17B1 Ser312Gly polymorphism and cancer risk in multiple ethnicities, yet these have produced inconsistent results. We therefore performed this comprehensive meta-analysis to attempt to provide a quality assessment of the association of interest. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of associations. After a systematic literature search of several major public databases, 20 studies involving 29,460 cases and 36,687 controls were included in this meta-analysis. No significant association was found between HSD17B1 Ser312Gly polymorphism and cancer risk. However, Ser312Gly polymorphism showed a significantly decreased risk for Caucasians (there were 44,284 Caucasians for analysis, comprising 19,889 cases and 24,395 controls) in the subgroup analysis by ethnicity (dominant: OR = 0.958, 95% CI = 0.919–0.998; and allele comparing: OR = 0.973, 95% CI = 0.947–0.999). And there was the same trend towards risk in the population-based (PB) controls (homozygous: OR = 0.951, 95% CI = 0.908–0.997 and allele comparing: OR = 0.976, 95% CI = 0.954–0.999), but not among Asians or hospital-based (HB) controls. In addition, no association was observed in the stratified analysis for breast cancer studies by source of control, ethnicity and quality score. These findings suggested that the HSD17B1 Ser312Gly polymorphism might confer genetic cancer susceptibility in an ethnic-dependent manner, especially among Caucasians. Well-designed, large-scale studies are warranted to validate these findings.

Polymorphisms in HSD17B1: Early Onset and Increased Risk of Alzheimer's Disease in Women with Down Syndrome

Background/Aims. Genetic variants that affect estrogen activity may influence the risk of Alzheimer's disease (AD). In women with Down syndrome, we examined the relation of polymorphisms in hydroxysteroid-17beta-dehydrogenase (HSD17B1) to age at onset and risk of AD. HSD17B1 encodes the enzyme 17β-hydroxysteroid dehydrogenase (HSD1), which catalyzes the conversion of estrone to estradiol. Methods. Two hundred and thirty-eight women with DS, nondemented at baseline, 31-78 years of age, were followed at 14-18-month intervals for 4.5 years. Women were genotyped for 5 haplotype-tagging single-nucleotide polymorphisms (SNPs) in the HSD17B1 gene region, and their association with incident AD was examined. Results. Age at onset was earlier, and risk of AD was elevated from two- to threefold among women homozygous for the minor allele at 3 SNPs in intron 4 (rs676387), exon 6 (rs605059), and exon 4 in COASY (rs598126). Carriers of the haplotype TCC, based on the risk alleles for these three SNPs, had an almost twofold increased risk of developing AD (hazard ratio = 1.8, 95% CI, 1.1-3.1). Conclusion. These findings support experimental and clinical studies of the neuroprotective role of estrogen.

The association between HSD17B1 Ser312Gly polymorphism and breast cancer risk: a meta-analysis including 31,053 subjects

There are increasing evidences that HSD17B1 plays a significant role in the development of breast cancer. However, published data on the association between HSD17B1 Ser312Gly polymorphism and breast cancer risk are inconclusive. In order to derive a more precise estimation of this relationship, a meta-analysis including 9 studies with 31,053 subjects was performed in this study. Crude ORs with 95% CIs were used to assess the strength of association between HSD17B1 Ser312Gly polymorphism and breast cancer risk. The pooled ORs were performed for codominant model (Gly/Gly versus Ser/Ser, Gly/Ser versus Ser/Ser), dominant model (Gly/Gly + Gly/Ser versus Ser/Ser), and recessive model (Gly/Gly versus Gly/Ser + Ser/Ser), respectively. Overall, no significant associations were detected between HSD17B1 Ser312Gly polymorphism and breast cancer susceptibility. However, in the stratified analysis by ethnicity, significant associations were observed in Caucasians for Gly/Gly versus Ser/Ser (OR = 0.91; 95% CI 0.83-1.00), Gly/Ser versus Ser/Ser (OR = 0.92; 95% CI 0.85-0.99), and Gly/Gly + Gly/Ser versus Ser/Ser (OR = 0.92; 95% CI 0.86-0.98). In conclusion, this study suggests that HSD17B1 312Gly allele may be a protective factor for breast cancer development in Caucasians. However, large sample and representative population-based studies with homogeneous breast cancer patients and well-matched controls are warranted to confirm this finding.

Analysis of 17beta-hydroxysteroid dehydrogenase types 5, 7, and 12 genetic sequence variants in breast cancer cases from French Canadian Families with high risk of breast and ovarian cancer

A family history and estrogen exposure are well-known risk factors for breast cancer. Members of the 17beta-hydroxysteroid dehydrogenase family are responsible for important steps in the metabolism of androgens and estrogens in peripheral tissues, including the mammary gland. The crucial biological function of 17beta-HSDs renders these genes good candidates for being involved in breast cancer etiology. This study screened for mutations in HSD17B7 and HSD17B12 genes, which encode enzymes involved in estradiol biosynthesis and in AKR1C3, which codes for 17beta-HSD type 5 enzyme involved in androgen and progesterone metabolism, to assess whether high penetrance allelic variants in these genes could be involved in breast cancer susceptibility. Mutation screening of 50 breast cancer cases from non-BRCA1/2 high-risk French Canadian families failed to identify germline likely high-risk mutations in HSD17B7, HSD17B12 and AKR1C3 genes. However, 107 sequence variants were identified, including seven missense variants. Assessment of the impact of missense variants on enzymatic activity of the corresponding enzymes revealed no difference in catalytic properties between variants of 17beta-HSD types 7 and 12 and wild-type enzymes, while variants p.Glu77Gly and p.Lys183Arg in 17beta-HSD type 5 showed a slightly decreased activity. Finally, a haplotype-based approach was used to determine tagging SNPs providing valuable information for studies investigating associations of common variants in these genes with breast cancer risk.

The 6q22.33 locus and breast cancer susceptibility

Recently, we identified a novel breast cancer susceptibility locus at 6q22.33 following a genome-wide association study in the Ashkenazi Jewish genetic isolate. To replicate these findings, we did a case-control association analysis on 6q22.33 (rs2180341) in an additional 487 Ashkenazi Jewish breast cancer cases and in an independent non-Jewish, predominantly European American, population of 1,466 breast cancer cases and 1,467 controls. We confirmed the 6q22.33 association with breast cancer risk in the replication cohorts [per-allele odds ratio (OR), 1.18; 95% confidence interval (95% CI), 1.04-1.33; P = 0.0083], with the strongest effect in the aggregate meta-analysis of 3,039 breast cancer cases and 2,616 Ashkenazi Jewish and non-Jewish controls (per-allele OR, 1.24; 95% CI, 1.13-1.36; P = 3.85 x 10(-7)). We also showed that the association was slightly stronger with estrogen receptor-positive tumors (per-allele OR, 1.35; 95% CI, 1.20-1.51; P = 2.2 x 10(-5)) compared with estrogen receptor-negative tumors (per-allele OR, 1.19; 95% CI, 0.97-1.47; P = 0.1). Furthermore, this study provides a novel insight into the functional significance of 6q22.33 in breast cancer susceptibility. Due to the stronger association of 6q22.33 with estrogen receptor-positive breast cancer, we examined the effect of candidate genes on estrogen receptor response elements. Upon transfection of overexpressed RNF146 in the MCF-7 breast cancer cell line, we observed diminished expression of an estrogen receptor response element reporter construct. This study confirms the association of 6q22.33 with breast cancer, with slightly stronger effect in estrogen receptor-positive tumors. Further functional studies of candidate genes are in progress, and a large replication analysis is being completed as part of an international consortium.