Epidemiology of keratinocyte carcinomas after organ transplantation.

Keratinocyte carcinoma (KC) is the most common type of cancer among white populations, but it is even more common among solid organ transplant recipients (OTRs). The most frequent histological type of KC among OTRs is cutaneous squamous cell carcinoma (cSCC), followed by basal cell carcinoma, although the reverse is seen in the general population. Metastatic cSCCs are more frequent, and mortality is increased compared with immunocompetent populations. There is strong evidence that the risk of KC among OTRs rises with increasing time after transplantation and older age at transplantation, and that KC is enhanced in those with sun-damaged skin. This evidence suggests that accelerated accumulation of genetic damage from several sources leads to excess KC in OTRs. We describe international variation in KC and focus on trends in immunosuppressive regimens, the role of ultraviolet susceptibility and exposure, and the contribution of genetics to tumour development. Further epidemiological studies are needed to address gaps in our understanding of the mediation of excess KC by immunosuppressive drugs, viral infection, genetic susceptibility, timing of relevant ultraviolet exposure or some combination of these factors.

Immunosuppressive Medications and Squamous Cell Skin Carcinoma: Nested Case-Control Study Within the Skin Cancer after Organ Transplant (SCOT) Cohort.

Organ transplant recipients (OTRs) have a substantially elevated risk of squamous cell skin carcinoma (SCSC), largely attributed to immunosuppressive medications used to prevent graft rejection, although data to support the role of newer drugs in SCSC risk are sparse. We investigated the association between immunosuppressive medications and SCSC risk among cardiac and renal transplant recipients in the SCOT cohort study. Incident cases were ascertained through medical record review after self-report of skin biopsy (n = 170). Controls without SCSC (n = 324) were matched to cases on sex, age, race, transplant year, hospital, donor type, organ transplanted, and time between transplantation and interview. Conditional logistic regression was used to evaluate the association between specific medications and SCSC. Users of the antimetabolite azathioprine were more than twice as likely to develop SCSC (odds ratio [OR] = 2.67, 95% confidence interval [CI] 1.23-5.76). In contrast, the newer antimetabolite preparations (i.e., mycophenolic acid [MPA]) were associated with lower SCSC risk (OR = 0.45, 95% CI 0.29-0.69). This inverse association between MPA and SCSC persisted among OTRs with no history of azathioprine use, even after adjustment for simultaneous use of the calcineurin inhibitor tacrolimus (OR = 0.52, 95% CI 0.32-0.84). Our data suggest that the increased risk of SCSC historically associated with azathioprine is not seen in OTRs prescribed newer regimens, including MPA and tacrolimus.

HPV-related cancers after solid organ transplantation in the United States.

Transplant recipients have elevated cancer risk including risk of human papillomavirus (HPV)-associated cancers of the cervix, anus, penis, vagina, vulva and oropharynx. We examined the incidence of HPV-related cancers in 187 649 US recipients in the Transplant Cancer Match Study. Standardized incidence ratios (SIRs) compared incidence rates to the general population, and incidence rate ratios (IRRs) compared rates across transplant subgroups. We observed elevated incidence of HPV-related cancers (SIRs: in situ 3.3-20.3, invasive 2.2-7.3), except for invasive cervical cancer (SIR 1.0). Incidence increased with time since transplant for vulvar, anal and penile cancers (IRRs 2.1-4.6 for 5+ vs. <2 years). Immunophenotype, characterized by decreased incidence with HLA DRB1:13 and increased incidence with B:44, contributed to susceptibility at several sites. Use of specific immunosuppressive medications was variably associated with incidence; for example, tacrolimus, was associated with reduced incidence for some anogenital cancers (IRRs 0.4-0.7) but increased incidence of oropharyngeal cancer (IRR 2.1). Thus, specific features associated with recipient characteristics, transplanted organs and medications are associated with incidence of HPV-related cancers after transplant. The absence of increased incidence of invasive cervical cancer highlights the success of cervical screening in this population and suggests a need for screening for other HPV-related cancers.

Genetic variation in CXCL12 and risk of cervical carcinoma: a population-based case-control study.

CXCL12 provides a chemotactic signal-directing leucocyte migration and regulates metastatic behaviour of tumour cells. We conducted a population-based case-control study to test the hypothesis that common genetic variation in CXCL12 individual single nucleotide polymorphism (SNP) alleles and haplotypes] is associated with the risk of cervical carcinoma. Cases (n = 917) were residents of western Washington State diagnosed with invasive squamous cell cervical carcinoma (SCC), invasive adenocarcinoma or adenosquamous carcinoma, or adenocarcinoma in situ of the cervix. Control participants (n = 849) were identified from the source population by random digit telephone dialling and frequency matched to cases on county and age. Nine CXCL12 tagSNPs chosen from the SeattleSNPs database were genotyped. The minor allele of intronic SNP rs266085 was inversely associated with cervical cancer under a recessive genetic effects model (OR = 0.74, 95% CI: 0.56-0.98). Among the ten common haplotypes inferred from the nine tagSNPs, one haplotype defined by minor alleles at 5'-flanking SNP rs17885289 and rs266085, and common alleles at the other seven SNPs occurred among 7.8% of cases and 10.6% of controls (dominant model OR = 0.72, 95% CI: 0.56-0.93; recessive model OR = 0.35, 95% CI: 0.12-0.97; and log-additive model OR = 0.72, 95% CI: 0.57-0.90). A stepwise procedure identified rs17885289, rs266085 and 3'-untranslated region (UTR) SNP rs266093 as the most parsimonious subset of SNPs necessary to define the haplotype inversely associated with cervical cancer risk in our study. A 3'-UTR SNP, rs1801157, previously found to be related to HIV pathogenesis, was not associated with cervical cancer risk. Further population-based studies are warranted to confirm these associations between genetic variation in CXCL12 and cervical cancer risk.

Cofactors with human papillomavirus in a population-based study of vulvar cancer.

BACKGROUND: Human papillomavirus (HPV) has been previously associated with vulvar cancer. In a population-based study, we examined whether exposure to HPV, cigarette smoking, or herpes simplex virus 2 (HSV2) increases the risk of this cancer. METHODS: Incident cases of in situ (n = 400) and invasive (n = 110) squamous cell vulvar cancer diagnosed among women living in the Seattle area from 1980 through 1994 were identified. Serum samples were analyzed for antibodies against specific HPV types and HSV2. HPV DNA in tumor tissue was detected by means of the polymerase chain reaction. In most analyses, case subjects were compared with population-based control subjects (n = 1403). Relative risks of developing vulvar cancer were estimated by use of adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Increased risks of in situ or invasive vulvar cancer were associated with HPV16 seropositivity (ORs = 3.6 [95% CI = 2.6-4.8] and 2.8 [95% CI = 1.7-4.7], respectively), current cigarette smoking (ORs = 6.4 [95% CI = 4.4-9.3] and 3.0 [95% CI = 1.7-5.3], respectively), and HSV2 seropositivity (ORs = 1.9 [95% CI = 1.4-2.6] and 1.5 [95% CI = 0.9-2.6], respectively). When the analysis was restricted to HPV16 DNA-positive tumors (in situ or invasive), the OR associated with HPV16 seropositivity was 4.5 (95% CI = 3.0-6.8). The OR for vulvar cancer was 18.8 (95% CI = 11.9-29.8) among current smokers who were HPV16 seropositive in comparison with never smokers who were HPV16 seronegative. CONCLUSIONS: Current smoking, infection with HPV16, and infection with HSV2 are risk factors for vulvar cancer. Risk appears particularly strong among women who are both current smokers and HPV16 seropositive.

Oral cancer risk in relation to sexual history and evidence of human papillomavirus infection.

BACKGROUND: Experimental models and analyses of human tumors suggest that oncogenic, sexually transmittable human papillomaviruses (HPVs) are etiologic factors in the development of oral squamous cell carcinoma (SCC). We conducted a population-based, case-control study to determine whether the risk of this cancer is related to HPV infection and sexual history factors. METHODS: Case subjects (n = 284) were 18-65-year-old residents of three counties in western Washington State who were newly diagnosed with oral SCC from 1990 through 1995. Control subjects (n = 477) similar in age and sex were selected from the general population. Serum samples were tested for HPV type 16 capsid antibodies. Exfoliated oral tissue collected from case and control subjects and tumor tissue from case subjects were tested for HPV DNA. Odds ratios (ORs) were calculated after adjusting for age, sex, cigarette smoking, and alcohol consumption. RESULTS: Among males only, oral SCC risk increased with self-reported decreasing age at first intercourse, increasing number of sex partners, and a history of genital warts. Approximately 26% of the tumors in case subjects contained HPV DNA; 16.5% of the tumors contained HPV type 16 DNA. The prevalence of oncogenic HPV types in exfoliated oral tissue was similar in case and control subjects. The ORs for HPV type 16 capsid seropositivity were 2.3 (95% confidence interval [CI] = 1.6-3.3) for all oral SCCs and 6.8 (95% CI = 3.0-15.2) for oral SCCs containing HPV type 16 DNA. The joint association of cigarette smoking and HPV type 16 capsid seropositivity with oral SCC (OR = 8.5; 95% CI = 5.1-14.4) was stronger than predicted from the sum of individual associations with current smoking (OR = 3.2; 95% CI = 2.0-5.2) and seropositivity (OR = 1.7; 95% CI = 1.1-2.6). CONCLUSIONS: HPV type 16 infection may contribute to the development of a small proportion of oral SCCs in this population, most likely in combination with cigarette smoking.

Serologic evidence of herpes simplex virus 1 infection and oropharyngeal cancer risk.

In vitro and animal models suggest that the herpes simplex virus 1 (HSV1) may contribute to the development of oropharyngeal squamous cell carcinoma (OSCC). To determine whether the risk of OSCC is related to infection with HSV1 in humans, we recruited 260 patients from 18 to 65 years old who were newly diagnosed with OSCC between 1990-1995 while residing in three western Washington State counties. For comparison, we recruited at random 445 controls frequency matched to cases on age and sex. Participants completed in-person interviews and provided serum samples that were tested for antibody response to HSV1. After adjusting for sex, cigarette smoking, alcohol consumption, age, and income, HSV1 antibody positivity was associated with a slightly increased risk of OSCC [adjusted odds ratio (OR), 1.3; 95% confidence interval (CI), 0.9-2.0]. The adjusted association between HSV1 antibody positivity and OSCC risk among those who were current cigarette smokers (OR, 4.2; CI, 2.4-7.1) was stronger than would be predicted based on the additive combination of smoking alone (OR, 2.3; CI, 1.2-4.2) and HSV1 seropositivity alone (OR, 1.0; CI, 0.6-1.7). There was suggestive evidence that the association between HSV1 infection and OSCC was similarly modified by evidence of HPV infection but no evidence of effect modification with alcohol consumption. This population-based study suggests that HSV1 may enhance the development of OSCC in individuals who are already at increased risk of the disease because of cigarette smoking or HPV infection.

Human papillomavirus 16 and 18 L1 serology compared across anogenital cancer sites.

Human papillomavirus (HPV) DNA has been detected in the great majority of cancers of the uterine cervix and anus, whereas the association of HPV DNA with cancer at other anogenital sites has produced less consistent results. This study was designed to compare HPV exposure among anogenital cancer cases and matched controls. Cases (1782) of anogenital cancer diagnosed in the Seattle area from 1978 to 1998 were identified and interviewed. Their responses were compared with those of 2383 age- and sex-matched controls. Blood was drawn at interview from both cases and controls and tested for antibodies to HPV-16 and HPV-18. Tissue blocks were tested for HPV DNA for 649 cases. Serum antibodies to HPV-16 were associated with in situ and invasive cancer at all sites among men and women with the exception of in situ penile cancer. Anti-HPV-18 antibodies were associated with cancers at all sites among women. The increased risk of cancer associated with HPV-16 seropositivity ranged from odds ratio = 1.8 (95% confidence interval, 1.4-2.5) for adenocarcinoma of the cervix to odds ratio = 5.9 (95% confidence interval, 3.4-10.3) for anal cancer in men. Associations between seroprevalence and cancers were stronger when analyses were restricted to HPV-16- or HPV-18 DNA-positive cases. HPV DNA was detected in >80% of cancers from all sites tested. HPV-16 DNA was the type most frequently detected at all sites (range, 40.9-82.2%). HPV-18 DNA was detected in 44.7% of adenocarcinomas of the cervix but detected much less often (2.6-18.1%) at other sites. These findings support an important role for HPV infection in anogenital cancer at all sites. Differences in the proportion of seropositives among HPV-16 DNA-positive cases by site suggest either that the immune response varies by site or that cancer development may lead to changes in antibody responses in a site-specific fashion.

Human papillomavirus and prognosis of invasive cervical cancer: a population-based study.

PURPOSE: To determine the association between human papillomavirus (HPV) type and prognosis of patients with invasive cervical carcinoma. PATIENTS AND METHODS: Patients diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage IB to IV cervical cancer between 1986 and 1997 while residents of three Washington State counties were included (n = 399). HPV typing was performed on paraffin-embedded tumor tissue using polymerase chain reaction methods. Patients were observed for a median of 50.8 months. Total mortality (TM) and cervical cancer-specific mortality (CCSM) were determined. Hazards ratios (HR) adjusted for age, stage, and histologic type were estimated using multivariable models. RESULTS: Eighty-six patients had HPV 18-related tumors and 210 patients had HPV 16-related tumors. Cumulative TM among patients with HPV 18-related tumors and among patients with HPV 16-related tumors were 33.7% and 27.6%, respectively; cumulative CCSM in these two groups were 26.7% and 18.1%, respectively. Compared with patients with HPV 16-related cancers, patients with HPV 18-related cancers were at increased risk for TM (HR(TM), 2.2; 95% confidence interval [CI], 1.3 to 3.6) and CCSM (HR(CCSM), 2.5; 95% CI, 1.4 to 4.4). The HPV18 associations were strongest for patients with FIGO stage IB or IIA disease (HR(TM), 3.1; 95% CI, 2.3 to 4.2; and HR(CCSM), 5.8; 95% CI, 3.9 to 8.7), whereas no associations were observed among patients with FIGO stage IIB to IV disease. Virtually identical associations were found in the subset of patients with squamous cell carcinoma (n = 219). CONCLUSION: HPV 18-related cervical carcinomas, particularly those diagnosed at an early stage, are associated with a poor prognosis. Elucidating the mechanism or mechanisms underlying this association could lead to new treatment approaches for patients with invasive cervical carcinoma.

Glutathione S-transferase M1 genotypes and the risk of anal cancer: a population-based case-control study.

Some studies have reported an association of the GSTM1-null genotype with the risk of smoking-related cancers, such as lung, bladder, and colon cancer. Because the risk of anal cancer is strongly associated with a history of cigarette smoking, we examined whether the GSTM1-null genotype is a susceptibility marker for anal cancer. We obtained peripheral blood specimens from residents of western Washington who were diagnosed with squamous or transitional cell tumor of the anus between April 1991 and June 1994. Eligible for inclusion were persons 18-74 years of age, with either invasive or in situ lesions. Specimens were also obtained from controls identified via random-digit dialing of western Washington households. We determined GSTM1 genotypes of 71 cases and 360 controls by PCR using primer pair 5'-AACTCCCTGAAAAGCTAAAGC-3' and 5'-GTTGGGCTCAAATATACGGTGG-3'. The frequency of the GSTM1-null genotype in controls was approximately 57%; this differed little in relation to age, sex and smoking status. The incidence of anal cancer appeared to be reduced in persons with the GSTM1-null genotype; only 39.4% of cases had this genotype (age-adjusted odds ratio = 0.5, 95% confidence interval = 0.3-0.9). This inverse association was restricted to persons who had ever smoked cigarettes and was present in both women and men (and in the latter, in both those who had and did not have a male sexual partner). Our data strongly suggest that persons with the GSTM1-null genotype are not at increased risk of anal cancer, and may well be at a decreased risk.

The p53 Arg72Pro polymorphism, human papillomavirus, and invasive squamous cell cervical cancer.

A. Storey et al. [Nature (Lond.), 393: 229-234, 1998)] reported a 7-fold increased risk of cervical cancer associated with having an Arg/Arg polymorphism at codon 72 of p53 compared with the Pro/Arg heterozygotes (odds ratio, 7.4; 95% confidence interval, 2.1-29.4). Complementary in vitro studies suggested that the HPV E6 oncoprotein more readily targets the arginine form, as opposed to the proline form, of p53 for degradation. We investigated the impact of this polymorphism in a population-based case-control study of invasive cervical cancer. Using a PCR assay to detect the p53 codon 72 polymorphism, we tested blood samples from 111 women with invasive squamous cell cancer of the cervix identified by a population-based registry and 164 random-digit telephone-dialed controls. The distribution of the genotype among control women was 38% heterozygous, 7% proline homozygous, and 55% arginine homozygous, and among the cases was 38%, 6%, and 56%, respectively. There was no increased risk of squamous cell invasive cervical cancer associated with homozygosity for the arginine allele (odds ratio, 1.0; 95% confidence interval, 0.6-1.7). Furthermore, there was no modification of this result by human papillomavirus (HPV) DNA status of the tumor, age, or smoking status. Among controls, there was no association between the polymorphism and HPV-16 L1 seropositivity. However, among case subjects, the codon 72 polymorphism may be related to HPV 16L1 seropositivity status.

CYP2D6 genotype and the incidence of anal and vulvar cancer.

The risks of anal and vulvar cancer are strongly related to cigarette smoking. Smokers are exposed to a substantial quantity of tobacco-specific nitrosamines, including 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNK is present in the mucus of the female genital tract. The enzyme debrisoquine 4-hydroxylase (CYP2D6) activates NNK and is present in foreskin kerotinocytes and cervical epithelial cells. A polymorphism for the gene CYP2D6 exists, and persons who possess alleles that are associated with reduced levels of CYP2D6 activity might be expected to be at a relatively lower risk of cancers arising from NNK exposure. To test this hypothesis, we conducted a case-control study to examine the association of CYP2D6 genotype and the incidence of anal and vulvar cancer among cigarette smokers in western Washington State. We tested for 14 alleles (*1-*12, *14, and *17) among cases (25 men and 43 women with anal cancer, 64 women with vulvar cancer) and controls (30 men and 110 women). Contrary to the hypothesis, cases were not less likely than controls to have one (43.9 versus 40.7%) or two (6.8 versus 4.3%) inactivating alleles (*3, *4, *5, *6, *7, *8, *11, or *12). There was a suggestion that, if anything, the combined anal and vulvar cancer risk increased (rather than decreased) with an increasing number of CYP2D6 inactivation alleles: odds ratio = 1.2, 95% confidence interval = 0.7-2.0 with one inactivating allele; odds ratio = 1.8, 95% confidence interval = 0.6-5.4 with two inactivating alleles. These results provide no support for the hypothesis that cigarette smokers who carry the CYP2D6 alleles that result in a low activity phenotype have a decreased risk of anogenital cancer.

The relationship of human papillomavirus-related cervical tumors to cigarette smoking, oral contraceptive use, and prior herpes simplex virus type 2 infection.

It has now been established that infection with human papillomavirus (HPV) is necessary for the development of most cervical cancers. HPV is not sufficient for the development of cancer. Other exposures or host factors are necessary for cancer to occur. As part of an ongoing, population-based case-control study of invasive cervical cancer, we investigated the role of cigarette smoking, oral contraceptive (OC) use, and herpes simplex virus type 2 (HSV-2) as potential cofactors with HPV in the development of cervical cancer. Residents of three counties in western Washington State who were diagnosed with invasive squamous cell cervical cancer (n = 314) from January 1986 through December 1992 were interviewed about their sexual, reproductive, contraceptive, and cigarette smoking histories. Similar information was obtained from control women identified through random digit dialing (n = 672). The sera from 206 cases and 522 controls were tested for both HPV 16 capsid antibodies and HSV-2 antibodies. PCR was used to test paraffin-embedded tumor tissues for the presence of HPV DNA types 6, 16, 18, 31, 33, 35, and 39. Women with cervical cancer were more likely to be current smokers at diagnosis than population controls [relative risk (RR), 2.5; 95% confidence interval (CI), 1.8-3.4]. The risk associated with smoking was present to a similar extent among women positive and negative for HPV as measured by HPV 16 capsid antibodies and HPV DNA in the tumor tissue (cases). OC use was only important if first use was at an early age, particularly ages < or = 17 years (RR, 2.3; 95% CI, 1.4-3.8). There was only a slight risk for cervical cancer associated with antibodies to HSV-2 (RR, 1.2; 95% CI, 0.9-1.7). However, when we stratified by markers of HPV exposure, we found a significant increase in risk associated with HSV-2 among women negative for HPV 16 antibodies (RR, 2.0; 95% CI, 1.3-3.0), which was strengthened when we confined our analysis to cases whose tumors were HPV DNA negative (RR, 3.6; 95% CI, 1.6-8.0). There was no indication that cigarette smoking, OC use, or HSV-2 infection influence the ability of HPV infection to cause invasive cervical cancer. OC use may only be important in the etiology of invasive squamous cell cervical tumors if the use occurs at a critical time in the development of a woman's reproductive tract, at ages < or = 17 years. The majority of risk associated with HSV-2 was confined to HPV-negative tumors, indicating a possible separate pathway to disease that may account for 5-10% of invasive cervical cancers.

Human papillomavirus and long-term oral contraceptive use increase the risk of adenocarcinoma in situ of the cervix.

We examined United States Surveillance, Epidemiology, and End Results incidence data and conducted a population-based case-control study to examine the role of human papillomavirus (HPV) and oral contraceptive (OC) use in the etiology of adenocarcinoma in situ of the cervix (ACIS). One hundred and fifty women diagnosed with ACIS and 651 randomly selected control women completed in-person interviews. The presence of HPV DNA in archival ACIS specimens was determined by E6 and L1 consensus PCR. Serum samples from case and control subjects were collected at interview, and antibodies to HPV-16 L1 and HPV-18 L1 were detected by virus-like particle capture assays. The overall prevalence of HPV DNA was 86.6%, with 39.0% positive for HPV-16 DNA, 52.4% positive for HPV-18 DNA, and 13.4% positive for more than one HPV type. The age-adjusted relative risk of ACIS associated with HPV-18 seropositivity was 3.3 (95% confidence interval 2.2-4.9). No increased risk was associated with antibodies to HPV-16 L1. Among women born after 1945, the relative risk increased with duration of OC use, with the highest risk for 12 or more years of use (odds ratio, 5.5; 95% confidence interval, 2.1-14.6) relative to nonusers. The detection of HPV DNA in 86.6% of ACIS and the strong association of ACIS with HPV-18 L1 seropositivity underscore the importance of HPV, particularly HPV-18, in the etiology of ACIS. In addition, long-term OC use may contribute to the pathogenesis of these tumors in some women.

HLA allelic variants encoding DR11 in diffuse and limited systemic sclerosis in Caucasian women.

OBJECTIVE: We investigated HLA class II alleles in women with systemic sclerosis (SSc), a rare disease that preferentially affects women. METHODS: Specific alleles of DRB1, DQA1 and DQB1 were determined by DNA-based HLA typing for women with SSc (n = 102) and healthy women (n = 533). All study subjects were Caucasian. DRB1, DQA1 and DQB1 allele frequencies of women with SSc were compared with those of healthy women. RESULTS: Among women with SSc, 29.4% (30/102) and among healthy women 10.7% (57/533) had DRB1*11. Allele frequencies were compared for women with SSc and healthy women (each woman has two alleles). The allele frequency of DRB1*11 was 15.7% (32/204 alleles) in SSc women and 5.8% (62/1066 alleles) in healthy women (P = 0.000002). The increase of DRB1*11 was found both in diffuse (P = 0.0001) and limited SSc (P = 0.002) (allele frequencies 15.0 and 17.2%, respectively). Among women with diffuse SSc, there was a disproportionate increase of the DRB1*1104 allele (P = 0.0004) with no increase of DRB1*1101 (P = 1.00). In contrast, in limited SSc the strongest association was with DRB1*1101 (P = 0.008), with a less significant increase of DRB1*1104 (P = 0.04). CONCLUSIONS: An increase of DRB1*11 in SSc is consistent with other reports. Although present in both diffuse and limited SSc disease subsets, the increase was predominantly due to over-representation of DRB1*1104 in women with diffuse SSc. Women with limited SSc had a preponderance of DRB1*1101, the most common allele in healthy women. DRB1*1104 and DRB1*1101 differ by a single amino acid at position 86, where the former has valine and the latter glycine.

Glutathione S-transferase M1 genotypes and the risk of vulvar cancer: a population-based case-control study.

Glutathione S-transferases (GSTs) facilitate the excretion of a variety of potential carcinogens. Some 50-60% of Caucasians are homozygous for the null allele of GSTM1, a gene responsible for the presence of one of these enzymes. The authors examined whether women with the GSTM1 null genotype are at altered risk of vulvar cancer. They obtained peripheral blood specimens from 18- to 79-year-old residents of King, Pierce, and Snohomish counties of western Washington who were diagnosed with vulvar cancer between April 1991 and June 1994. Blood specimens were also obtained from controls identified via random digit telephone dialing of western Washington households. The authors determined the GSTM1 genotype of 137 cases (120 in situ and 17 invasive cases) and 248 controls. The frequency of the GSTM1 null genotype was 46.7% among cases and 57.3% among controls. The age-adjusted odds ratio associated with the GSTM1 null genotype was 0.7 (95% confidence interval: 0.4, 1.0). Among current smokers of cigarettes, the age-adjusted odds ratio associated with the GSTM1 null genotype was 0.5 (95% confidence interval: 0.2, 0.9), differing little between heavy and light smokers. Our data suggest that women with the GSTM1 null genotype are not at increased risk of vulvar cancer.

Glutathione S-transferase M1 genotypes and the risk of squamous carcinoma of the cervix: a population-based case-control study.

The authors determined the GSTM1 genotype of 190 Caucasian women with invasive squamous cell cervical cancer in western Washington State between January 1986 and June 1994 and of 206 controls. It was found that 53% of cases and 57% of controls had the GSTM1 null genotype. The age-adjusted odds ratio associated with GSTM1 null genotype was 0.8 (95% confidence interval 0.6, 1.3). The lack of association between cervical cancer risk and GSTM1 genotype was true both for smokers and nonsmokers of cigarettes and for heavy and light smokers. These data suggest that women with the GSTM1 null genotype are not at increased risk of cervical cancer.

HTLV-I and HTLV-II world-wide distribution: reanalysis of 4,832 immunoblot results.

Mapping the geographic distribution of human T-lymphotrophic virus types 1 and 2 (HTLV-I and -II) has been complicated because conventional serologic approaches cannot distinguish between these 2 viruses. To more precisely define the epidemiology of HTLV-I and HTLV-II, we evaluated a convenience sample of 4,832 HTLV-I immunoblot results from over 140,000 samples screened for HTLV-I, collected in 16 countries for 35 separate studies. An algorithm that compares reactivity against p19 and p24, 2 gag (HTLV-I core) proteins, was employed to characterize the immunoblots: type I, p19 stronger than p24 (presumptive HTLV-I), type 2, p24 stronger than p19 (presumptive HTLV-II), or indeterminate (p19 and p24 weakly positive or p19 weakly positive in the presence of p21e). Geographic areas could be grouped into 4 patterns. Patterns A (> 75% type I) and B (> 75% type 2) were usually observed where the specific type of HTLV or its characteristic diseases had been found. Pattern C (mixed type 1 and 2 pattern) was observed predominantly in intravenous-drug-using and other populations in which both virus types have been reported. Pattern D (> 10% indeterminate), suggests the presence of non-specific reactivity, perhaps resulting from exposure to non-virus-related antigens or an HTLV-related virus. HTLV-I predominates in southern Japan, the South Pacific, parts of West Africa, and in Afro-populations of the Western hemisphere. HTLV-II clusters in Native American populations and among intravenous drug users. Pattern-D areas in Africa and Venezuela might prove to be fertile in the search for new and variant HTLV virus types.