- Email: [email protected]
Simian virus 40 infectionin lymphoproliferative disorders
CORRESPONDENCE
IGT or diabetes 50
Prevalence (%)
45
Simian virus 40 infection in lymphoproliferative disorders
Diabetes 50
Non-Hispanic whites Amish
45
40
40
35
35
30
30
25
25
20
20
15
15
10
10
5
5
0
0 40–49
50–59
60–74
Overall
40–49
50–59
60–74
Overall
Age (years)
Prevalence of impaired glucose tolerance (IGT) or type 2 diabetes (left) and of type 2 diabetes (right) in non-Hispanic whites and Amish individuals
ancestors arrived on US shores in the 18th century, maintain religious and cultural beliefs that preclude regular use of modern conveniences such as electrical appliances, telephones, and cars, and have a physically active lifestyle. By comparison, the 200 million typical Americans living alongside them have, over the past 250 years, willingly adopted advances of modern technology, making life less physically demanding. Both groups have similar diets. Surprisingly, Amish adults are just as obese as the general US white population (mean body-mass index 27·9 kg/m2 [SD 4·6] in Amish3 vs 27·0 kg/m2 [5·1] in non-Hispanic whites4) and almost as likely to have an abnormal oral glucose tolerance test (ie, either IGT or diabetes; figure). However, manifest diabetes is about half as prevalent in the Amish as it is in the general population (6·7% in Amish3 vs 14·3% in nonHispanic whites;4 prevalence ratio 0·54, 95% CI 0·23–0·84; figure). The apparently low rate of conversion from IGT to diabetes suggested by these cross-sectional data is supported by follow-up glucose tolerance tests 2–5 years later in more than 100 Amish individuals with IGT (unpublished data). The lower prevalence of diabetes in the Amish suggests that physical activity has a protective effect against type 2 diabetes, independent of body-mass index. This observation is in agreement with the Da Qing Study.5 Furthermore, stratification of our Amish individuals by age (figure) shows that the protective effect of the 18th century lifestyle against diabetes occurs over all
88
age-groups from 40 to 74 years,3 suggesting that physical activity has durable effects. Because dieting attempts are frequently unsuccessful, these observations suggest that increasing physical activity is an appealing way to reduce the risk of diabetes. The concept of incorporating physical activity into daily life seems more feasible than dedicated exercise sessions, but will require societal changes including urban planning issues, transportation policies, and employer participation. *Soren Snitker, Braxton D Mitchell, Alan R Shuldiner University of Maryland School of Medicine, Baltimore, MD 21201, USA (e-mail: [email protected]) 1
2
3
4
5
Knowler WC, Barrett-Connor E, Fowler SE, et al, for the Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002; 346: 393–403. Tuomilehto J, Lindstrom J, Eriksson JG, et al, for the Finnish Diabetes Prevention Study Group. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343–50. Hsueh W-C, Mitchell BD, Aburomia R, et al. Diabetes in the Old Order Amish: characterization and heritability analysis of the Amish Family Diabetes Study. Diabetes Care 2000; 23: 595–601. Kuczmarski RJ, Carroll MD, Flegal KM, Troiano RP. Varying body mass index cutoff points to describe overweight prevalence among US adults: NHANES III (1988 to 1994). Obes Res 1997; 5: 542–48. Pan XR, Li GW, Hu YH, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance: the Da Qing IGT and Diabetes Study. Diabetes Care 1997; 20: 537–44.
Sir—Lymphomas are associated with several molecular pathways.1 Two reports suggested a role for simian virus 40 (SV40) in lymphomagenesis.2,3 On the basis of the paradigm of other lymphoma-related viruses,1 SV40 has several features predictive of a pathogenetic role: it is lymphotropic, exerts its transforming activity through large T antigen, and is capable of transforming B cells in vitro and inducing B-cell lymphomas in animals.4 We investigated the presence of SV40 in 500 individuals referred to Italian or Spanish institutions with lymphoproliferative disorders. DNA from frozen samples was tested for PCR suitability by amplification of a 748 bp BCL6 gene fragment. SV40 DNA detection was based on three PCR reactions that targeted 5⬘ and 3⬘ sequences of large T antigen. Primers included: SVTagP1 and SVTagP2 (156 bp 5⬘-sequence amplimer); SVfor2 and SVrev (574 bp 5⬘-sequence amplimer); TA1 and TA2 (441 bp 3⬘sequence amplimer).2,3 In dilution experiments with SV40 plasmid (pZEO-SVE) DNA, all PCR (45 sensitivity, cycles) attained 10–4 allowing the detection of ten SV40 genomes among 200 000 human genome equivalents. Assignment of SV40 positivity required positive signals in all three PCR assays and amplimer validation by DNA sequencing. A masked pilot experiment readily identified SV40-positive mesotheliomas, but not SV40-negative tumours. On the basis of the adopted criteria, no case of lymphoproliferative disorder scored positive for SV40 (table; see http://image.thelancet.com/02cor1102 0webtable.pdf for detailed histological types). Conversely, PCR assays detected human herpesvirus 8 (HHV8) infection in 11 of 11 primary effusion lymphomas (eight AIDS-related, three non-AIDS-related), and EpsteinBarr virus (EBV) infection in 64 of 500 cases. With respect to SV40, 17 of 500 (3·4%) cases yielded SV40 sequences in SVTagP1/SVTagP2 and SVfor2/ SVrev reactions, but none was positive by the 3⬘-region TA1/TA2 reaction, nor with primers TA3 (nucleotides 2621–2645) and TA5 (3005–3026), mapping in the proximity of the TA1 and TA2 primers . Lack of positivity cannot be ascribed to primer mismatches, because TA1/TA2 primers anneal to conserved regions, whereas most polymorphisms
THE LANCET • Vol 361 • January 4, 2003 • www.thelancet.com
For personal use. Only reproduce with permission from The Lancet Publishing Group.
CORRESPONDENCE
B-cell malignancies (n=371)* T-cell malignancies (n=15)* AIDS-related lymphomas (n=68) Post-transplant lymphoproliferative disorders (n=31) Reactive lymphoproliferative disorders (n=15)
SV40
EBV
HHV8
0 0 0 0 0
12 1 36 15 0
3 8 0
Positivity for SV40 defined as presence of SV40 DNA in all three PCR assays. *Immunocompetent individuals.
Positivity for SV40, EBV, and HHV8 among southern European patients with lymphoproliferative disorders
affect sequences within the amplimer.5 Speculative explanations might involve partial deletions or rearrangements of viral genome as well as amplification of currently uncharacterised viruses homologous to SV40. Our results indicate that SV40 is not involved in lymphoma in patients from southern Europe. One explanation of this discrepancy concerns differences in the geographical origin of tumour samples—ie, Italy and Spain in this study and southwestern USA in other reports.2,3 Geographic variability cannot be ascribed to differences in the contamination of poliovaccines, since contaminated lots were distributed in the USA and southern Europe over a similar period. A second hypothesis concerns differences in the SV40 detection techniques. Conceivably, extensive screening for 3⬘-regions of large T antigen and sequencing of all positive amplimers might have rendered our approach more selective for SV40 infection. Since our assays allow detection of 10 copies of SV40 genome in 200 000 human genome equivalents, we can rule out clonal SV40 infection of the tumour population.1 Moreover, since our assay sensitivity is 2 logs higher than required for detecting other lymphoma-related viruses, and since SV40-induced lymphomagenesis in rodents entails the presence of SV40 in all tumour cells,3,4 viral loads inferior to our sensitivity threshold are unlikely to be of pathogenetic relevance. This study was supported by grants from Istituto Superiore di Sanità, Programma Nazionale di Ricerca sull’AIDS–Progetto Patologia, Clinica e Terapia dell’AIDS, Rome, Italy; by Cofin 2000–MIUR, Rome, Italy; and by CNR-MIUR Progetto Strategico Oncologia.
Daniela Capello, Davide Rossi, Giovanni Gaudino, Antonino Carbone, *Gianluca Gaidano *Haematology Unit, Division of Internal Medicine (DC, DR, *GG), and Laboratory of Molecular Biology (GG), Department of Medical Sciences and IRCAD, Amedeo Avogadro University of Eastern Piedmont, 28100 Novara, Italy; and Division of Pathology, IRCCS-Centro di Riferimento Oncologico, Aviano, Italy (AC). (e-mail: [email protected])
1
2
3
4
5
Dalla-Favera R, Gaidano G. Molecular biology of lymphomas. In: De Vita VT, Hellman S, Rosenberg SA, eds. Cancer: principles and practice of oncology, 6th edn. Philadelphia: JB Lippincott, 2001: 2215–35. Shivapurkar N, Harada K, Reddy J, et al. Presence of simian virus 40 DNA sequences in human lymphomas. Lancet 2002; 359: 851–52. Vilchez RA, Madden CR, Kozinetz C, et al. Association between simian virus 40 and non-Hodgkin lymphoma. Lancet 2002; 359: 817–23. Butel JS, Lednicky JA. Cell and molecular biology of simian virus 40: implications for human infections and disease. J Natl Cancer Inst 1999; 91: 119–34. Rizzo P, Carbone M, Fisher SG, et al. Simian virus 40 is present in most United States mesotheliomas, but it is rarely present in nonHodgkin’s lymphoma. Chest 1999; 116: 470S–73S.
New NHS guidelines for PSA testing in primary care Sir—The UK Department of Health has recently published the Prostate Cancer Risk Management Programme, which is currently being distributed to general practitioners. We wish to comment on several issues that we feel this information pack fails to deal with satisfactorily. First, the Department of Health’s advice is that testing for prostatespecific antigen (PSA) should be avoided within a week of a digital rectal examination, and at least 48 h after vigorous exercise. The largest study on the effect of digital rectal examinations on PSA concentrations1 showed that there was no effect in patients with a PSA concentration below 20 ng/mL. The authors felt that the difference seen in patients with a PSA above this concentration were not of clinical significance. Cycling for 15 min has been shown to increase PSA concentrations up to threefold,2 but other forms of exercise do not seem to have any effect.3
THE LANCET • Vol 361 • January 4, 2003 • www.thelancet.com
We therefore feel that patients would be better advised specifically not to cycle—which they may not even regard as vigorous exercise— within a week of their PSA test. Indeed, a UK government task force recommends, as we do, that only bicycle riding should be avoided before PSA testing.4 This advice would prevent unnecessary additional visits and wasting of primary healthcare resources. Second, the covering letter to the resource pack states that the information is for advising and counselling of symptom-free men. However, information contained within the pack does not make a clear distinction between symptomatic and symptom-free men, which is likely to be misleading. They comment that early prostate cancer does not usually cause lower-urinarytract symptoms. However, they fail to stress the importance of PSA testing in this symptomatic group to diagnose the cases of advanced disease that could otherwise be missed on clinical examination. This is an important group of patients who should be offered PSA testing, because if they are found to have an advanced prostate cancer, their symptoms are likely to be improved more promptly with hormone manipulation. PSA testing among this group of symptomatic patients would also avoid the potential problem of treating patients for what is assumed to be benign disease, only to discover later that they have carcinoma of the prostate. Among 171 consecutive patients presenting to us over the past 3 years with advanced prostate cancer, 84 had an initial PSA concentration of more than 50 ng/mL. In many cases, the general practitioners volunteered that they initially thought that the prostate felt benign and were surprised by the high PSA concentration. We agree that careful counselling should be given before offering a PSA test, since the result can raise difficult issues for patient and clinician. However, we feel strongly that it should not be omitted in symptomatic men older than 50 years. The guidelines need to be clarified. *Robin Weston, Nigel Parr Arrowe Park Hospital, Wirral CH49 5PE, UK (e-mail: [email protected]) 1
Crawford ED, Schultz MJ, Clejan S, et al.The effect of digital rectal examination on prostate specific-antigen levels. JAMA 1992; 267: 2227–28.
89
For personal use. Only reproduce with permission from The Lancet Publishing Group.
IGT or diabetes 50
Prevalence (%)
45
Simian virus 40 infection in lymphoproliferative disorders
Diabetes 50
Non-Hispanic whites Amish
45
40
40
35
35
30
30
25
25
20
20
15
15
10
10
5
5
0
0 40–49
50–59
60–74
Overall
40–49
50–59
60–74
Overall
Age (years)
Prevalence of impaired glucose tolerance (IGT) or type 2 diabetes (left) and of type 2 diabetes (right) in non-Hispanic whites and Amish individuals
ancestors arrived on US shores in the 18th century, maintain religious and cultural beliefs that preclude regular use of modern conveniences such as electrical appliances, telephones, and cars, and have a physically active lifestyle. By comparison, the 200 million typical Americans living alongside them have, over the past 250 years, willingly adopted advances of modern technology, making life less physically demanding. Both groups have similar diets. Surprisingly, Amish adults are just as obese as the general US white population (mean body-mass index 27·9 kg/m2 [SD 4·6] in Amish3 vs 27·0 kg/m2 [5·1] in non-Hispanic whites4) and almost as likely to have an abnormal oral glucose tolerance test (ie, either IGT or diabetes; figure). However, manifest diabetes is about half as prevalent in the Amish as it is in the general population (6·7% in Amish3 vs 14·3% in nonHispanic whites;4 prevalence ratio 0·54, 95% CI 0·23–0·84; figure). The apparently low rate of conversion from IGT to diabetes suggested by these cross-sectional data is supported by follow-up glucose tolerance tests 2–5 years later in more than 100 Amish individuals with IGT (unpublished data). The lower prevalence of diabetes in the Amish suggests that physical activity has a protective effect against type 2 diabetes, independent of body-mass index. This observation is in agreement with the Da Qing Study.5 Furthermore, stratification of our Amish individuals by age (figure) shows that the protective effect of the 18th century lifestyle against diabetes occurs over all
88
age-groups from 40 to 74 years,3 suggesting that physical activity has durable effects. Because dieting attempts are frequently unsuccessful, these observations suggest that increasing physical activity is an appealing way to reduce the risk of diabetes. The concept of incorporating physical activity into daily life seems more feasible than dedicated exercise sessions, but will require societal changes including urban planning issues, transportation policies, and employer participation. *Soren Snitker, Braxton D Mitchell, Alan R Shuldiner University of Maryland School of Medicine, Baltimore, MD 21201, USA (e-mail: [email protected]) 1
2
3
4
5
Knowler WC, Barrett-Connor E, Fowler SE, et al, for the Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002; 346: 393–403. Tuomilehto J, Lindstrom J, Eriksson JG, et al, for the Finnish Diabetes Prevention Study Group. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343–50. Hsueh W-C, Mitchell BD, Aburomia R, et al. Diabetes in the Old Order Amish: characterization and heritability analysis of the Amish Family Diabetes Study. Diabetes Care 2000; 23: 595–601. Kuczmarski RJ, Carroll MD, Flegal KM, Troiano RP. Varying body mass index cutoff points to describe overweight prevalence among US adults: NHANES III (1988 to 1994). Obes Res 1997; 5: 542–48. Pan XR, Li GW, Hu YH, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance: the Da Qing IGT and Diabetes Study. Diabetes Care 1997; 20: 537–44.
Sir—Lymphomas are associated with several molecular pathways.1 Two reports suggested a role for simian virus 40 (SV40) in lymphomagenesis.2,3 On the basis of the paradigm of other lymphoma-related viruses,1 SV40 has several features predictive of a pathogenetic role: it is lymphotropic, exerts its transforming activity through large T antigen, and is capable of transforming B cells in vitro and inducing B-cell lymphomas in animals.4 We investigated the presence of SV40 in 500 individuals referred to Italian or Spanish institutions with lymphoproliferative disorders. DNA from frozen samples was tested for PCR suitability by amplification of a 748 bp BCL6 gene fragment. SV40 DNA detection was based on three PCR reactions that targeted 5⬘ and 3⬘ sequences of large T antigen. Primers included: SVTagP1 and SVTagP2 (156 bp 5⬘-sequence amplimer); SVfor2 and SVrev (574 bp 5⬘-sequence amplimer); TA1 and TA2 (441 bp 3⬘sequence amplimer).2,3 In dilution experiments with SV40 plasmid (pZEO-SVE) DNA, all PCR (45 sensitivity, cycles) attained 10–4 allowing the detection of ten SV40 genomes among 200 000 human genome equivalents. Assignment of SV40 positivity required positive signals in all three PCR assays and amplimer validation by DNA sequencing. A masked pilot experiment readily identified SV40-positive mesotheliomas, but not SV40-negative tumours. On the basis of the adopted criteria, no case of lymphoproliferative disorder scored positive for SV40 (table; see http://image.thelancet.com/02cor1102 0webtable.pdf for detailed histological types). Conversely, PCR assays detected human herpesvirus 8 (HHV8) infection in 11 of 11 primary effusion lymphomas (eight AIDS-related, three non-AIDS-related), and EpsteinBarr virus (EBV) infection in 64 of 500 cases. With respect to SV40, 17 of 500 (3·4%) cases yielded SV40 sequences in SVTagP1/SVTagP2 and SVfor2/ SVrev reactions, but none was positive by the 3⬘-region TA1/TA2 reaction, nor with primers TA3 (nucleotides 2621–2645) and TA5 (3005–3026), mapping in the proximity of the TA1 and TA2 primers . Lack of positivity cannot be ascribed to primer mismatches, because TA1/TA2 primers anneal to conserved regions, whereas most polymorphisms
THE LANCET • Vol 361 • January 4, 2003 • www.thelancet.com
For personal use. Only reproduce with permission from The Lancet Publishing Group.
CORRESPONDENCE
B-cell malignancies (n=371)* T-cell malignancies (n=15)* AIDS-related lymphomas (n=68) Post-transplant lymphoproliferative disorders (n=31) Reactive lymphoproliferative disorders (n=15)
SV40
EBV
HHV8
0 0 0 0 0
12 1 36 15 0
3 8 0
Positivity for SV40 defined as presence of SV40 DNA in all three PCR assays. *Immunocompetent individuals.
Positivity for SV40, EBV, and HHV8 among southern European patients with lymphoproliferative disorders
affect sequences within the amplimer.5 Speculative explanations might involve partial deletions or rearrangements of viral genome as well as amplification of currently uncharacterised viruses homologous to SV40. Our results indicate that SV40 is not involved in lymphoma in patients from southern Europe. One explanation of this discrepancy concerns differences in the geographical origin of tumour samples—ie, Italy and Spain in this study and southwestern USA in other reports.2,3 Geographic variability cannot be ascribed to differences in the contamination of poliovaccines, since contaminated lots were distributed in the USA and southern Europe over a similar period. A second hypothesis concerns differences in the SV40 detection techniques. Conceivably, extensive screening for 3⬘-regions of large T antigen and sequencing of all positive amplimers might have rendered our approach more selective for SV40 infection. Since our assays allow detection of 10 copies of SV40 genome in 200 000 human genome equivalents, we can rule out clonal SV40 infection of the tumour population.1 Moreover, since our assay sensitivity is 2 logs higher than required for detecting other lymphoma-related viruses, and since SV40-induced lymphomagenesis in rodents entails the presence of SV40 in all tumour cells,3,4 viral loads inferior to our sensitivity threshold are unlikely to be of pathogenetic relevance. This study was supported by grants from Istituto Superiore di Sanità, Programma Nazionale di Ricerca sull’AIDS–Progetto Patologia, Clinica e Terapia dell’AIDS, Rome, Italy; by Cofin 2000–MIUR, Rome, Italy; and by CNR-MIUR Progetto Strategico Oncologia.
Daniela Capello, Davide Rossi, Giovanni Gaudino, Antonino Carbone, *Gianluca Gaidano *Haematology Unit, Division of Internal Medicine (DC, DR, *GG), and Laboratory of Molecular Biology (GG), Department of Medical Sciences and IRCAD, Amedeo Avogadro University of Eastern Piedmont, 28100 Novara, Italy; and Division of Pathology, IRCCS-Centro di Riferimento Oncologico, Aviano, Italy (AC). (e-mail: [email protected])
1
2
3
4
5
Dalla-Favera R, Gaidano G. Molecular biology of lymphomas. In: De Vita VT, Hellman S, Rosenberg SA, eds. Cancer: principles and practice of oncology, 6th edn. Philadelphia: JB Lippincott, 2001: 2215–35. Shivapurkar N, Harada K, Reddy J, et al. Presence of simian virus 40 DNA sequences in human lymphomas. Lancet 2002; 359: 851–52. Vilchez RA, Madden CR, Kozinetz C, et al. Association between simian virus 40 and non-Hodgkin lymphoma. Lancet 2002; 359: 817–23. Butel JS, Lednicky JA. Cell and molecular biology of simian virus 40: implications for human infections and disease. J Natl Cancer Inst 1999; 91: 119–34. Rizzo P, Carbone M, Fisher SG, et al. Simian virus 40 is present in most United States mesotheliomas, but it is rarely present in nonHodgkin’s lymphoma. Chest 1999; 116: 470S–73S.
New NHS guidelines for PSA testing in primary care Sir—The UK Department of Health has recently published the Prostate Cancer Risk Management Programme, which is currently being distributed to general practitioners. We wish to comment on several issues that we feel this information pack fails to deal with satisfactorily. First, the Department of Health’s advice is that testing for prostatespecific antigen (PSA) should be avoided within a week of a digital rectal examination, and at least 48 h after vigorous exercise. The largest study on the effect of digital rectal examinations on PSA concentrations1 showed that there was no effect in patients with a PSA concentration below 20 ng/mL. The authors felt that the difference seen in patients with a PSA above this concentration were not of clinical significance. Cycling for 15 min has been shown to increase PSA concentrations up to threefold,2 but other forms of exercise do not seem to have any effect.3
THE LANCET • Vol 361 • January 4, 2003 • www.thelancet.com
We therefore feel that patients would be better advised specifically not to cycle—which they may not even regard as vigorous exercise— within a week of their PSA test. Indeed, a UK government task force recommends, as we do, that only bicycle riding should be avoided before PSA testing.4 This advice would prevent unnecessary additional visits and wasting of primary healthcare resources. Second, the covering letter to the resource pack states that the information is for advising and counselling of symptom-free men. However, information contained within the pack does not make a clear distinction between symptomatic and symptom-free men, which is likely to be misleading. They comment that early prostate cancer does not usually cause lower-urinarytract symptoms. However, they fail to stress the importance of PSA testing in this symptomatic group to diagnose the cases of advanced disease that could otherwise be missed on clinical examination. This is an important group of patients who should be offered PSA testing, because if they are found to have an advanced prostate cancer, their symptoms are likely to be improved more promptly with hormone manipulation. PSA testing among this group of symptomatic patients would also avoid the potential problem of treating patients for what is assumed to be benign disease, only to discover later that they have carcinoma of the prostate. Among 171 consecutive patients presenting to us over the past 3 years with advanced prostate cancer, 84 had an initial PSA concentration of more than 50 ng/mL. In many cases, the general practitioners volunteered that they initially thought that the prostate felt benign and were surprised by the high PSA concentration. We agree that careful counselling should be given before offering a PSA test, since the result can raise difficult issues for patient and clinician. However, we feel strongly that it should not be omitted in symptomatic men older than 50 years. The guidelines need to be clarified. *Robin Weston, Nigel Parr Arrowe Park Hospital, Wirral CH49 5PE, UK (e-mail: [email protected]) 1
Crawford ED, Schultz MJ, Clejan S, et al.The effect of digital rectal examination on prostate specific-antigen levels. JAMA 1992; 267: 2227–28.
89
For personal use. Only reproduce with permission from The Lancet Publishing Group.