MEDLINE Abstracts: Prostate Cancer and Genetics
Visakorpi T
Ann Chir Gynaecol 1999;88(1):11-6
Despite the substantial clinical importance of prostate cancer, the molecular mechanisms underlying the development and progression of the disease are poorly understood. The aim of molecular genetics is to reveal the genetic alterations and genes that are involved in disease processes. Linkage analysis have already implicated four chromosomal loci that may harbour prostate cancer susceptibility genes. In addition, chromosomal alterations in prostate tumors have been studied using several techniques, such as comparative genomic hybridization. These analyses have indicated that losses of chromosomes 6q, 8p, 10q, 13q, and 16q, as well as gains of 7, 8q, and Xq are particularly common in prostate cancer. There is also a strong evidence, that genes, such as androgen receptor gene (AR), e-cadherin, and PTEN, are involved in the development and progression of prostate cancer. However, the target genes for most of the above mentioned chromosomal alterations as well as the genes predisposing to prostate cancer have not been cloned yet. The identification of those genes should be the utmost goal of basic research of prostate cancer, today.
Ekman P
Eur Urol 1999;35(5-6):362-9
Prostate cancer is the most common malignancy found in males; however, little is as yet known regarding what initiates the disease. The incidence is highest among American Blacks and lowest in the East Asian population. Subtypes of the disease include familial clustering and a hereditary form (9%) supporting genetic events to be involved in prostate cancer pathogenesis. Chromosomal abberations so far identified as being frequently occurring in this disease seem to be related to later phases of disease progression. However, research finding the responsible promoting genetic alteration is rapidly progressing. To explain the varied geographical distribution of the disease, the environment also has to be taken into account. Risk factors identified so far include obesity, animal fat, red meat consumption and certain toxins containing cadmium, while vegetables, cereals and vitamin D seem to be protective. It is reasonable to believe that, in the near future, we will be able to identify persons at risk of acquiring the disease and then inform them how to adjust their lifestyle to avoid early progression of the malignancy.
Cooney KA, Tsou HC, Petty EM, Miesfeldt S, Ping XL, Gruener AC, Peacocke M
Clin Cancer Res 1999 Jun;5(6):1387-91
Epidemiological studies have demonstrated that men with a family history of prostate cancer are at an increased risk for this disease. This important observation has led a number of research teams, including our own, to collect DNA samples and clinical data from prostate cancer families, with the goal of localizing and characterizing prostate cancer susceptibility genes. The candidate tumor suppressor gene PTEN (also called MMAC1) has recently been shown to be somatically altered in several common malignancies, including cancers of the brain, kidney, skin, thyroid, endometrium, breast, and prostate. Germ-line mutations in this gene, which maps to chromosome 10q23, have been associated with Cowden disease, an autosomal dominant cancer predisposition syndrome that is characterized by multiple hamartomas. Although prostate cancer is not typically associated with Cowden disease, previous studies of sporadic prostate cancers demonstrate loss of heterozygosity at 10q23 loci in approximately 25% of cases. We, therefore, hypothesized that germ-line mutations in the PTEN gene may predispose to prostate cancer in a subset of families, particularly those in which cancers of the breast, kidney, and/or thyroid also segregate. To test this hypothesis, DNA was isolated from whole blood of 11 prostate cancer patients from 10 unrelated families. Four of the 10 families met the previously established clinical criteria for hereditary prostate cancer. Eight of the II men had at least one second primary malignancy, including cases of neuroendocrine cancer, glioblastoma multiforme, melanoma, kidney, and thyroid cancer. Although we identified some common as well as some unique polymorphisms, no nonsense or missense mutations were identified in any of the 11 samples. To further examine the possibility that PTEN mutations contribute to prostate cancer predisposition, we also studied the probands from each of 10 families with early-onset and/or multiple individuals with prostate cancer. Sequence analysis of the PTEN gene in these 10 men also revealed no mutations or novel polymorphisms. We conclude that germ-line mutations in the PTEN are unlikely to contribute in a significant way to the inherited predisposition to prostate cancer.
Gibbs M, Stanford JL, McIndoe RA, Jarvik GP, Kolb S, Goode EL, Chakrabarti L, Schuster EF, Buckley VA, Miller EL, Brandzel S, Li S, Hood L, Ostrander EA
Am J Hum Genet 1999 Mar;64(3):776-87
Combining data from a genomic screen in 70 families with a high risk for prostate cancer (PC) with data from candidate-region mapping in these families and an additional 71 families, we have localized a potential hereditary PC-susceptibility locus to chromosome 1p36. Because an excess of cases of primary brain cancer (BC) have been observed in some studies of families with a high risk for PC, and because loss of heterozygosity at 1p36 is frequently observed in BC, we further evaluated 12 families with both a history of PC and a blood relative with primary BC. The overall LOD score in these 12 families was 3.22 at a recombination fraction (theta) of .06, with marker D1S507. On the basis of an a priori hypothesis, this group was stratified by age at diagnosis of PC. In the younger age group (mean age at diagnosis <66 years), a maximum two-point LOD score of 3.65 at straight theta = .0 was observed, with D1S407. This linkage was rejected in both early- and late-onset families without a history of BC (LOD scores -7.12 and -6.03, respectively, at straight theta = .0). After exclusion of 3 of the 12 families that had better evidence of linkage to previously described PC-susceptibility loci, linkage to the 1p36 region was suggested by a two-point LOD score of 4.74 at straight theta = .0, with marker D1S407. We conclude that a significant proportion of these families with both a high risk for PC and a family member with BC show linkage to the 1p36 region.
Makridakis NM, Ross RK, Pike MC, Crocitto LE, Kolonel LN, Pearce CL, Henderson BE, Reichardt JK
Lancet 1999 Sep 18;354(9183):975-8
Background: Prostate cancer is a very common disease in more-developed countries, but its cause is largely unknown. It is an androgen-dependent cancer, and androgens have been proposed as having a substantial role in predisposition to the disease. Thus, variations in androgen metabolism genes may affect risk of this disease.
Methods: We screened 216 African-American and 172 Hispanic men with prostate cancer, and 261 African-American and 200 Hispanic healthy men (controls), from a large prospective cohort study (the Hawaii-Los Angeles Multiethnic Cohort Study) for a mis-sense substitution in the human prostatic (or type II) steroid 5alpha-reductase (SRD5A2) gene, the product of which controls metabolic activation of testosterone to dihydrotestosterone. This mis-sense substitution results in an alanine residue at codon 49 being replaced with threonine (A49T). We also reconstructed this mutation in the SRD5A2 cDNA, and overexpressed the enzyme in mammalian tissue culture cells.
Findings: The A49T aminoacid substitution in the SRD5A2 gene increased the risk of clinically significant disease 7.2-fold in African-American men (95% CI=2.17-27.91; p=0.001) and 3.6-fold in Hispanic men (1.09-12.27; p=0.04). The mutant enzyme had a higher in-vitro Vmax than the normal enzyme (9.9 vs 1.9 nmol min(-1) mg(-1)).
Interpretation: The A49T variant of the SRD5A2 gene may be a significant contributor to the incidence of prostate cancer in African-American and Hispanic men in Los Angeles. We estimate that the population attributable risk due to this aminoacid substitution for clinically significant disease is about 8% in both populations. Increased conversion of testosterone to dihydrotestosterone catalysed by this variant steroid 5alpha-reductase enzyme may be the cause of the increased risk.
Chang HC, Miyamoto H, Marwah P, Lardy H, Yeh S, Huang KE, Chang C George
Proc Natl Acad Sci U S A 1999 Sep 28;96(20):11173-7
Our earlier report suggested that androst-5-ene-3beta,7beta-diol (Delta(5)-androstenediol or Adiol) is a natural hormone with androgenic activity and that two potent antiandrogens, hydroxyflutamide (Eulexin) and bicalutamide (Casodex), fail to block completely the Adiol-induced androgen receptor (AR) transactivation in prostate cancer cells. Here, we report the development of a reporter assay to screen several selective steroids with anti-Adiol activity. Among 22 derivatives/metabolites of dehydroepiandrosterone, we found 4 steroids [no. 4, 1,3,5(10)-estratriene-17alpha-ethynyl-3, 17beta-diol; no. 6, 17alpha-ethynyl-androstene-diol; no. 8, 3beta, 17beta-dihydroxy-androst-5-ene-16-one; and no. 10, 3beta-methylcarbonate-androst-5-ene-7,17-dione] that have no androgenic activity and could also block the Adiol-induced AR transactivation in prostate cancer PC-3 cells. Interestingly, these compounds, in combination with hydroxyflutamide, further suppressed the Adiol-induced AR transactivation. Reporter assays further showed that these four anti-Adiol steroids have relatively lower glucocorticoid, progesterone, and estrogenic activity. Together, these data suggest some selective steroids might have anti-Adiol activity, which may have potential clinical application in the battle against the androgen-dependent prostate cancer growth.
Visakorpi T
Ann Chir Gynaecol 1999;88(1):11-6
Despite the substantial clinical importance of prostate cancer, the molecular mechanisms underlying the development and progression of the disease are poorly understood. The aim of molecular genetics is to reveal the genetic alterations and genes that are involved in disease processes. Linkage analysis have already implicated four chromosomal loci that may harbour prostate cancer susceptibility genes. In addition, chromosomal alterations in prostate tumors have been studied using several techniques, such as comparative genomic hybridization. These analyses have indicated that losses of chromosomes 6q, 8p, 10q, 13q, and 16q, as well as gains of 7, 8q, and Xq are particularly common in prostate cancer. There is also a strong evidence, that genes, such as androgen receptor gene (AR), e-cadherin, and PTEN, are involved in the development and progression of prostate cancer. However, the target genes for most of the above mentioned chromosomal alterations as well as the genes predisposing to prostate cancer have not been cloned yet. The identification of those genes should be the utmost goal of basic research of prostate cancer, today.
Ekman P
Eur Urol 1999;35(5-6):362-9
Prostate cancer is the most common malignancy found in males; however, little is as yet known regarding what initiates the disease. The incidence is highest among American Blacks and lowest in the East Asian population. Subtypes of the disease include familial clustering and a hereditary form (9%) supporting genetic events to be involved in prostate cancer pathogenesis. Chromosomal abberations so far identified as being frequently occurring in this disease seem to be related to later phases of disease progression. However, research finding the responsible promoting genetic alteration is rapidly progressing. To explain the varied geographical distribution of the disease, the environment also has to be taken into account. Risk factors identified so far include obesity, animal fat, red meat consumption and certain toxins containing cadmium, while vegetables, cereals and vitamin D seem to be protective. It is reasonable to believe that, in the near future, we will be able to identify persons at risk of acquiring the disease and then inform them how to adjust their lifestyle to avoid early progression of the malignancy.
Cooney KA, Tsou HC, Petty EM, Miesfeldt S, Ping XL, Gruener AC, Peacocke M
Clin Cancer Res 1999 Jun;5(6):1387-91
Epidemiological studies have demonstrated that men with a family history of prostate cancer are at an increased risk for this disease. This important observation has led a number of research teams, including our own, to collect DNA samples and clinical data from prostate cancer families, with the goal of localizing and characterizing prostate cancer susceptibility genes. The candidate tumor suppressor gene PTEN (also called MMAC1) has recently been shown to be somatically altered in several common malignancies, including cancers of the brain, kidney, skin, thyroid, endometrium, breast, and prostate. Germ-line mutations in this gene, which maps to chromosome 10q23, have been associated with Cowden disease, an autosomal dominant cancer predisposition syndrome that is characterized by multiple hamartomas. Although prostate cancer is not typically associated with Cowden disease, previous studies of sporadic prostate cancers demonstrate loss of heterozygosity at 10q23 loci in approximately 25% of cases. We, therefore, hypothesized that germ-line mutations in the PTEN gene may predispose to prostate cancer in a subset of families, particularly those in which cancers of the breast, kidney, and/or thyroid also segregate. To test this hypothesis, DNA was isolated from whole blood of 11 prostate cancer patients from 10 unrelated families. Four of the 10 families met the previously established clinical criteria for hereditary prostate cancer. Eight of the II men had at least one second primary malignancy, including cases of neuroendocrine cancer, glioblastoma multiforme, melanoma, kidney, and thyroid cancer. Although we identified some common as well as some unique polymorphisms, no nonsense or missense mutations were identified in any of the 11 samples. To further examine the possibility that PTEN mutations contribute to prostate cancer predisposition, we also studied the probands from each of 10 families with early-onset and/or multiple individuals with prostate cancer. Sequence analysis of the PTEN gene in these 10 men also revealed no mutations or novel polymorphisms. We conclude that germ-line mutations in the PTEN are unlikely to contribute in a significant way to the inherited predisposition to prostate cancer.
Gibbs M, Stanford JL, McIndoe RA, Jarvik GP, Kolb S, Goode EL, Chakrabarti L, Schuster EF, Buckley VA, Miller EL, Brandzel S, Li S, Hood L, Ostrander EA
Am J Hum Genet 1999 Mar;64(3):776-87
Combining data from a genomic screen in 70 families with a high risk for prostate cancer (PC) with data from candidate-region mapping in these families and an additional 71 families, we have localized a potential hereditary PC-susceptibility locus to chromosome 1p36. Because an excess of cases of primary brain cancer (BC) have been observed in some studies of families with a high risk for PC, and because loss of heterozygosity at 1p36 is frequently observed in BC, we further evaluated 12 families with both a history of PC and a blood relative with primary BC. The overall LOD score in these 12 families was 3.22 at a recombination fraction (theta) of .06, with marker D1S507. On the basis of an a priori hypothesis, this group was stratified by age at diagnosis of PC. In the younger age group (mean age at diagnosis <66 years), a maximum two-point LOD score of 3.65 at straight theta = .0 was observed, with D1S407. This linkage was rejected in both early- and late-onset families without a history of BC (LOD scores -7.12 and -6.03, respectively, at straight theta = .0). After exclusion of 3 of the 12 families that had better evidence of linkage to previously described PC-susceptibility loci, linkage to the 1p36 region was suggested by a two-point LOD score of 4.74 at straight theta = .0, with marker D1S407. We conclude that a significant proportion of these families with both a high risk for PC and a family member with BC show linkage to the 1p36 region.
Makridakis NM, Ross RK, Pike MC, Crocitto LE, Kolonel LN, Pearce CL, Henderson BE, Reichardt JK
Lancet 1999 Sep 18;354(9183):975-8
Background: Prostate cancer is a very common disease in more-developed countries, but its cause is largely unknown. It is an androgen-dependent cancer, and androgens have been proposed as having a substantial role in predisposition to the disease. Thus, variations in androgen metabolism genes may affect risk of this disease.
Methods: We screened 216 African-American and 172 Hispanic men with prostate cancer, and 261 African-American and 200 Hispanic healthy men (controls), from a large prospective cohort study (the Hawaii-Los Angeles Multiethnic Cohort Study) for a mis-sense substitution in the human prostatic (or type II) steroid 5alpha-reductase (SRD5A2) gene, the product of which controls metabolic activation of testosterone to dihydrotestosterone. This mis-sense substitution results in an alanine residue at codon 49 being replaced with threonine (A49T). We also reconstructed this mutation in the SRD5A2 cDNA, and overexpressed the enzyme in mammalian tissue culture cells.
Findings: The A49T aminoacid substitution in the SRD5A2 gene increased the risk of clinically significant disease 7.2-fold in African-American men (95% CI=2.17-27.91; p=0.001) and 3.6-fold in Hispanic men (1.09-12.27; p=0.04). The mutant enzyme had a higher in-vitro Vmax than the normal enzyme (9.9 vs 1.9 nmol min(-1) mg(-1)).
Interpretation: The A49T variant of the SRD5A2 gene may be a significant contributor to the incidence of prostate cancer in African-American and Hispanic men in Los Angeles. We estimate that the population attributable risk due to this aminoacid substitution for clinically significant disease is about 8% in both populations. Increased conversion of testosterone to dihydrotestosterone catalysed by this variant steroid 5alpha-reductase enzyme may be the cause of the increased risk.
Chang HC, Miyamoto H, Marwah P, Lardy H, Yeh S, Huang KE, Chang C George
Proc Natl Acad Sci U S A 1999 Sep 28;96(20):11173-7
Our earlier report suggested that androst-5-ene-3beta,7beta-diol (Delta(5)-androstenediol or Adiol) is a natural hormone with androgenic activity and that two potent antiandrogens, hydroxyflutamide (Eulexin) and bicalutamide (Casodex), fail to block completely the Adiol-induced androgen receptor (AR) transactivation in prostate cancer cells. Here, we report the development of a reporter assay to screen several selective steroids with anti-Adiol activity. Among 22 derivatives/metabolites of dehydroepiandrosterone, we found 4 steroids [no. 4, 1,3,5(10)-estratriene-17alpha-ethynyl-3, 17beta-diol; no. 6, 17alpha-ethynyl-androstene-diol; no. 8, 3beta, 17beta-dihydroxy-androst-5-ene-16-one; and no. 10, 3beta-methylcarbonate-androst-5-ene-7,17-dione] that have no androgenic activity and could also block the Adiol-induced AR transactivation in prostate cancer PC-3 cells. Interestingly, these compounds, in combination with hydroxyflutamide, further suppressed the Adiol-induced AR transactivation. Reporter assays further showed that these four anti-Adiol steroids have relatively lower glucocorticoid, progesterone, and estrogenic activity. Together, these data suggest some selective steroids might have anti-Adiol activity, which may have potential clinical application in the battle against the androgen-dependent prostate cancer growth.
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