biological markers for exposures epidemiology 243 molecular epidemiology of cancer
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Biological Markers for Exposures
Epidemiology 243
Molecular Epidemiology of Cancer
Early Studies
• MacMahon: Geographical correlation of urinary estrogen concentrations with cancer of the breast (1974)
• Cole & MacMahon: Urinary and blood estrogens and breast cancer in case-control studies (1969,1982, 1983)
• McMichael: The relationship between cancer mortality and serum cholesterol concentrations (1984)
Recent Studies
• Aflatoxins and hepatitis B on liver cancer in a cohort study, including measurements of urinary metabolites and nucleic acid adducts of aflatoxin (Ross, 1992, 1994)
• The relationship between HPV and cervical cancer (Munoz, 1992, Bosch, 1995)
Application of biomarkers in Epidemiology
Molecular markers can be applied to increase the accuracy of measurements
• of genetic and other acquired susceptibility to disease;
• of exposures that may cause or prevent disease;• of exposures that confound or modify the
associations between risk and other exposures• of disease itself• of factors that may determine the outcome of the
disease such as precursors and stages
Application of biomarkers in Epidemiology
Biomarkers may also be used • to reduce the time interval between the relevant
exposure and measurement of the putative effect• To increase the yield of information on disease
pathogenesis• To increase the cost-effectiveness of
epidemiological studies. More information is gained per unit cost.
Biomarker in Epidemiology: Biomarkers of Biological Agents
• Biological agents associated with chronic infection and subsequent development of cancer are measured using serological or nucleic acid markers.
Biomarker in Epidemiology: Biomarkers of Biological Agents• HPV DNA by PCR-based assays
HPV infection is often transient, especially in young women so that repeated sampling is required to assess persistent HPV infections
Classification of Cervical Squamous Neoplasia
Dysplasia PapS. CIN scale Bethesda
Normal 1 Normal Normal
Infla. Atypia 2a Infla. atypia Normal
Koilocyt.Atypia 2b Koilocyto a. LG SIL
Mild dysplasia 3 CIN1 LG SIL
Moderate dysp. 3 CIN2 HG SIL
Severe dysp. 3 CIN3 HG SIL
Ca. in situ 4 CIN3 HG SIL
Invasive ca. 5 Invasive ca Invasive ca
HPV Testing and Typing
• HPV infection is the main cause of cervical cancer. Transient in women. Only 10-20% persistent infections are at risk of neoplasia
• About 70 subtypes, of which 25 are tropic for genital tract. Those are subdivided into three categories:
HPV Testing and Typing
• HPV can be tested and typed by dot blot hybridization, southern blot hybridization, Hybrid Capture and PCR
• High sensitivity but relatively low specificity, particular among young women
• HPV typing has great potential as a primary screening tool for cervical cancer.
Biomarker in Epidemiology: Biomarkers of Biological Agents
HBV infection by serological assays.
• There are serological markers that distinguish between past and persistent infections. HBV DNA detection in sera further refines the assessment of exposure.
HBV
Gender Case
N %
Control
N %
P Value
Male 159 (77.94 )
287(69.16) 0.0221
Female 45 (22.06) 128(30.84)
204 415
Gender distribution among cases and controls
Self-reported hepatitis virus infection type
Hepatitis History Case
N %
Control
N %
Crude OR (95%CI)
Adjusted OR (95% CI)
No 108(60.34) 354(90.08) 1 1
HAV 16(8.94) 19(4.84) 2.77(1.38~5.57) 2.67(1.27~5.60)
HBV 55(30.73) 19(4.40) 11.30(6.22~20.5) 14.52(7.38~28.6)
HDV 0 (0) 1(0.26)
The relationship between liver cirrhosis and liver cancer
Liver cirrhosis Case
N %
Control
N %
Crude OR (95%CI)
Adjusted OR (95% CI)
No 149(86.6) 355(99.2)
Yes 23 (13.4) 3 (0.8) 18.3(5.40~61.8) 22.1(6.11~79.9)
The relationship between HBV vaccine and liver cancer
HBV vaccine Case
N %
Control
N %
Crude OR (95%CI)
Adjusted OR (95% CI)
No 157(96.32)
293(86.14) 1 1
Yes 6(3.68) 47(13.9) 0.24(0.10~0.57) 0.24(0.10~0.60)
The distribution of HBsAg among cases and controls
HBsAg Case
N %
Control
N %
Crude OR (95%CI)
Adjusted OR (95% CI)
Negative 72(35.29) 312(75.36) 1 1
Positive 132(64.71) 102(24.64) 5.59(3.95~8.18) 5.06(3.45~7.43)
HBsAg Case
N %
Control
N %
Crude OR (95%CI)
Adjusted OR (95% CI)
Negative 183(91.04) 403(97.11) 1 1
Positive 18 (8.96) 12 (2.89) 3.49(1.66~7.33) 3.21(1.46~7.06)
The distribution of anti-HCV among cases and controls
TYPE HBsAg HBsAb HBeAg HBeAb HBcAb Crude OR
(95%CI)
Adjusteda
(95%CI)
2 - - - - - 1.00 1.00
1 - + - - - 0.24 (0.09~0.63)* 0.23 (0.09~0.61)*
3 - - - - + 1.00 (0.49~2.03) 1.02 (0.49~2.11)
1 + - - + + 4.74 (2.48~9.06)* 3.91 (1.99~7.66)*
2 + - - - + 8.9 (4.00~19.73)* 7.68 (3.23~18.31)*
3 + - + - + 12.50 (4.78~32.73)* 11.55 (4.18~31.90)*
Most frequent HBV infection spectrum in cases and controls
Mildewed food intake
GSTM1 Case
N %
Controls
N %
Crude OR(95% CI)
Adjusted OR(95%CI)
Further adjusted OR(95%CI)
No Normal 45(25.6) 126(32.9) 1 1 1
Yes Normal 17(9.7) 29(7.6) 1.64(0.82~3.27) 1.81(0.87~3.76)
2.69(1.15~6.30)
No Null 86(48.9) 193(50.4) 1.25(0.82~1.91) 1.20(0.77~1.87)
1.38(0.84~2.25)
Yes Null 28(15.9) 35(9.1) 2.24(1.23~4.09) 2.67(1.36~5.23)
4.13(1.85~9.24)
The possible interaction between GSTM1 and mildewed food
The possible interaction between GSTT1 and HBV
HBsAg GSTT1 Case
N %
Control
N %
Crude OR
(95% CI)
Adjusted
OR (95%CI)
Further adjusted OR(95%CI)
No Normal 36(19.0) 146(37.1) 1
1 1
Yes Normal 67(35.3) 54(13.7) 5.03(3.02~8.39) 4.49(2.63~7.67) 4.48(2.62~7.67)
No Null 27(14.2) 150(38.1) 0.73(0.42~1.26) 0.73(0.41~1.29) 0.68(0.38~1.22)
Yes Null 60(31.6) 44(11.2) 5.53(3.25~9.43) 4.91(2.81~8.60) 5.04(2.85~13.9)
Raw water drinking
HBsAg Case
N %
Control
N %
Crude OR
(95% CI)
Adjusted
OR (95%CI)
No Negative 32(17.30) 184(51.40) 1 1
Yes Negative 30(16.22) 83(23.18) 2.08(1.19~3.64) 1.84(1.03~3.28)
No Positive 63(34.05) 63(17.60) 5.75(3.44~9.60) 5.25(3.04~9.06)
Yes Positive 60(32.43) 28(7.82) 12.32(6.86~22.11) 9.66(5.22~17.89)
The interaction between HBsAg and raw water drinking
Mildew food intake
HBsAg Case
N %
Control
N %
Crude OR
(95% CI)
Adjusted
OR (95%CI)
No Negative 46(24.08) 151(62.13) 1 1
Yes Negative 21(10.99) 52(12.87) 2.20(1.21~4.00) 2.47(1.32~4.63)
No Positive 97(21.53) 87(21.53) 6.08(3.97~9.33) 5.41(3.46~8.45)
Yes Positive 27(14.14) 14(3.47) 10.52(5.13~21.58) 10.82(5.09~22.98)
The interaction between HBsAg and mildewed food intake
Alcohol drinking
HBsAg Case
N %
Control
N %
Crude OR
(95% CI)
Adjusted
OR (95%CI)
No Negative 34(17.71) 157(38.20) 1 1
Yes Negative 35(18.23) 153(37.23) 1.06(0.63~1.78) 1.06(0.56~2.00)
No Positive 53(27.60) 70(36.46) 5.00(2.92~8.54) 4.36(2.47~7.68)
Yes Positive 49(11.92) 52(12.65) 6.22(3.71~10.41) 6.19(3.13~12.25).
The interaction between HBsAg and alcohol drinking
Anti-HCV HBsAg Case
N %
Control
N %
Crude OR
(95% CI)
Adjusted
OR (95%CI)
No Negative 63(31.19) 304(73.08) 1 1
Yes Negative 6(2.97) 10(2.40) 2.90(1.02~8.26) 2.63(0.88~7.85)
No Positive 120(59.41) 100(24.04) 5.79(3.96~8.46) 5.20(3.49~7.76)
Yes Positive 13(6.44) 2(0.48) 31.37(6.91~ 42.44)
23.99(5.09~ 13.12)
The interaction between HBsAg and anti-HCV
The interaction between HBsAg and family history of liver cancer
Anti-HCV HBsAg Case
N %
Control
N %
Crude OR
(95% CI)
Adjusted
OR (95%CI)
No Negative 58(28.29) 284(68.27) 1 1
Yes Negative 14(6.83) 30(7.21) 2.285(1.41~4.58) 2.33(1.13~4.81)
No Positive 94(45.85) 93(22.36) 4.95(3.31~7.40) 4.52(2.96~6.92)
Yes Positive 39(19.02) 9(2.16) 21.22(9.75~46.19) 24.14(10.34~ 6.35)
Selected Variables OR ( 95%CI )
Age 0.95 (0.93~0.98)
Gender 1.71 (0.80~3.65)
Education 0.56 (0.38~0.82)
Mildewed food intake 2.64 (1.39~4.99)
Refrigerator using at home 0.30 (0.13~0.68)
Raw water drinking 1.19 (0.65~2.19)
Pack-year of smoking 1.00 (0.98~1.03)
Alcohol drinking 1.38 (0.72~2.62)
Characteristics
optimistic 0.40 (0.23~0.69)
Depressed 4.35 (1.41~13.45)
Family history of liver cancer 4.81 (2.41~9.60)
HBsAg 6.93 (4.07~11.78)
Anti-HCV 3.49(1.10~11.07)
GSTM1 1.87 (1.09~3.21)
GSTT1 0.72 (0.43~1.21)
Multivariate Logistic Regression Analysis
Major Risk Factors for Stomach Cancer in Chinese Population
• Helicobacter pylori was the first bacterium to be officially recognized as a cancer-causing agent.
Major Risk Factors for Stomach Cancer in Chinese Population
• Helicobacter pylori Infection. Nitrates and nitrites are substances commonly found in cured meats, some drinking water, and certain vegetables, that can be converted by Helicobacter pylori, into compounds that have been found to cause stomach cancer in animals.
Figure 1a: H.pylori and gastric cancer - Prospective studies: meta-analysis of non cardia cancer
cases.
Figure 1b: H.pylori and gastric cancer - Prospective studies: meta-analysis of cardia cancer cases.
H. Pylori Infection and Stomach Cancer in Whites at MSKCC
H. Pylori case/control OR
no 69/54 1.00
yes 67/15 3.50 (1.80-6.79)
Infection rates:
21.7% in controls
49.3% in cases
Biomarker in Epidemiology: Biomarkers of Internal Dose
• Biomarker of internal dose of external chemical exposures are measurements of a parent compound or its metabolites in an accessible biological matrix, such as serum or urine
Biomarker in Epidemiology: Biomarkers of Internal Dose
• The half-life of the external agent or its metabolites in the body
• The pattern of the exposure it is measuring (regular exposure or infrequent exposure)
• Whether the secular trends have occurred in that exposure (e.g., smoking cessation)
• Direct or indirect influence of the disease
Urine Test Kit for Tobacco Use
Marker for Internal Dose
Fat-soluble substance such as DDT metabolites
• Persist over time
• Will not be affected by disease status
DDT
• DDT (dichlorodiphenyltrichloroethane) is a commercial organochlorine insecticide that has been used in countries around the world. It has been used widely on agricultural crops as well as for "vector control" - the control of insects that carry such diseases as malaria and typhus
DDT
• This organochlorine insecticide can be considered as the pesticide of the greatest historical significance, due to its effect on the environment, agriculture, and human health.
• First synthesized by a German graduate student in 1873, it was rediscovered by Dr. Paul Mueller, a Swiss entomologist, in 1939 while searching for a long-lasting insecticide for the clothes moth.
DDT
• DDT subsequently proved to be extremely effective against flies and mosquitoes, ultimately leading to the award of the Nobel Prize in medicine for Dr. Mueller in 1948.
• Effective January 1, 1973 the Environmental Protection Agency (EPA) officially canceled all uses of DDT, but not before more than 1 billion kilograms of DDT had been introduced into the United States.
Biomarker of Dietary Intake
• Whether it is a good indicator of intake
• Whether it is a long- or short-term marker
• Whether there is a need for multiple measurements
• Whether it is acceptable for researcher and the subject
• Whether it is compatible with study design
Main component of green Tea Catechins: (-)-Epigallocatechin gallate ((-)EGCg)
Adduct as Biomarker
• Chemicals can bind covalently to cellular macromolecules such as nucleic acids and protein. The product of this addition of a chemical moiety to a macromolecule is termed an “adduct”
Adduct as Biomarker
• Adduct may be highly specific for carcinogen of interest, but not necessarily specific for a given exposure because of multiple sources of carcinogen with environment
• Adduct formation normally occurs after the metabolic activation of the carcinogen; DNA repair may follow adduct formation
Adduct as Biomarker
The persistent of the adducts is determined by
• Chemical stability of the adduct itself
• The turnover of macromolecule to which the chemical is bound
Adduct as Biomarker
• A half-life of adducts on proteins (HB and albumin): a few weeks to months
• A half-life of DNA adducts: a few hours to several years depending on cell type concerned
Adduct as Biomarker
• Adducts can be measured at
• Blood
• Exfoliated cells
• Tissue
• Urine (metabolites of adducts)
Group 1: Carcinogenic to Humans
• Tobacco Smoking• Tobacco Products, Smokeless• 4-Aminobiphenyl (4-ABP)• Benzene• Carmium• Chromium• 2-Naphthylamine (2-NA)• Nickel• Polonium-210 (Radon)• Vinyl Chloride
Group 2A: Probably Carcinogenic to Humans
• Acrylonitrile• Benzo[a]pyrene• Benzo[a]anthracene• 1,3-Butadiene• Dibenz(a,h)anthracene• Formaldehyde• N-Nitrosodiethylamine• N-Nitrosodimethylamine
PHIP DNA Adducts
