α-Methylacyl-CoA racemase expression and lethal prostate cancer in the Physicians' Health Study and Health Professionals Follow-up Study

BACKGROUND

α-Methylacyl-CoA racemase (AMACR) is an enzyme that serves as a diagnostic biomarker of prostate cancer in clinical practice. Recent studies suggest that low AMACR expression is associated with biochemical recurrence and the development of fatal disease.

METHODS

We conducted a prospective cohort study among 920 men aged 47-84 years, who were diagnosed with prostate cancer in the Physicians' Health Study and the Health Professionals Follow-up Study cohorts, and whose resected tissue specimens were available for immunohistochemical analysis. We used Cox proportional hazards regression to evaluate the association of AMACR expression with lethal prostate cancer over a 20-year follow-up period.

RESULTS

In total, 68 men died from prostate cancer, and an additional 18 developed bony metastases during follow-up. We found that lower AMACR intensity was associated with higher prostate-specific antigen levels (P = 0.003) and more advanced clinical stage (P = 0.06) at diagnosis, and a nonsignificant trend for higher risk of lethal outcomes. The hazard ratio (HR) comparing the lowest to the highest quartile of AMACR expression intensity was 1.53 ((95% CI: 0.86-2.73), P-for-trend across quartiles = 0.07); this trend was further attenuated after adjustment for age, Gleason score, stage, and cohort with a HR of 1.24 (95% CI: 0.69-2.22), P-for-trend = 0.23.

CONCLUSIONS

Low AMACR expression in primary tumor specimens was not independently associated with the development of metastatic and lethal prostate cancer after treatment over a 20-year follow-up period, after adjustment for important clinical covariates at diagnosis.

Common polymorphisms in the adiponectin and its receptor genes, adiponectin levels and the risk of prostate cancer

BACKGROUND

Adiponectin, an insulin-sensitizing adipokine, is inversely associated with adiposity and prostate cancer risk and progression. However, the role of genetic variation in the adiponectin (ADIPOQ) and receptor genes (ADIPOR1/R2) in prostate cancer is largely unknown.

METHODS

In a nested case-control study of 1,286 cases and 1,267 controls within the Physicians' Health Study, we evaluated 29 common single-nucleotide polymorphisms (SNP) in ADIPOQ (n = 13), ADIPOR1 (n = 5), and ADIPOR2 (n = 11) in relation to the risk of prostate cancer. In subgroups, we also evaluated the association of genotype and circulating adiponectin levels (n = 951) and prostate tumor expression of insulin receptor (IR) and insulin-like growth factor 1 (IGF-IR) receptor (n = 181).

RESULTS

Among the 12 tagging polymorphisms in ADIPOQ, four (rs266729, rs182052, rs822391, and rs2082940) were significantly associated (P < 0.05) with overall prostate cancer risk, with no significant difference by tumor grade or clinical stage. Two of the risk SNPs (rs266729 and rs182052) plus four other SNPs (rs16861209, rs17366568, rs3774261, and rs7639352) were also associated with plasma adiponectin levels, and three of these (rs1686109, rs17366568, and rs3774261) were also significantly associated with IR expression in prostate tumor tissue. One additional SNP was associated with IGFI-R tumor tissue expression (rs16861205). None of the 16 variants in ADIPOR1/R2 were related to cancer risk or circulating adiponectin levels.

CONCLUSIONS

Common variants in the adiponectin gene were associated with prostate cancer risk, plasma adiponectin levels, and IR or IGF-IR expression in the prostate tumor.

IMPACT

These genotype-phenotype associations support the biological relevance of adiponectin for prostate carcinogenesis, particularly in earlier stages of development.

Long-term aspirin use and the risk of total, high-grade, regionally advanced and lethal prostate cancer in a prospective cohort of health professionals, 1988-2006

Experimental studies suggest a role for aspirin in the chemoprevention of prostate cancer and epidemiological evidence supports a modest inverse association between regular aspirin use and prostate cancer risk, especially for advanced disease. In a prospective cohort study of 51,529 health professionals aged 40-75 years at baseline, we evaluated long-term aspirin use and the incidence of total, high-grade (Gleason 8-10, n = 488), regionally advanced (T3b-T4 or N1, n = 228) and lethal prostate cancer (M1, bony metastases or prostate cancer death, n = 580) from 1988-2006. We used Cox proportional hazards regression to evaluate risk associated with frequency (days/week), quantity (tablets/week), recency and duration of aspirin use after multivariable adjustment for confounders and other predictors of prostate cancer risk. A total of 4,858 men were diagnosed with prostate cancer during the 18-year study period. Men taking ≥ 2 adult-strength aspirin tablets a week had a 10% lower risk of prostate cancer (p-for-trend = 0.02). For regionally advanced cancer, we observed no significant associations with aspirin use. For high-grade and lethal disease, men taking ≥ 6 adult-strength tablets/week experienced similar reductions in risk hazard ratio [HR = 0.72 (95% confidence intervals [CI]: 0.54, 0.96) and HR = 0.71 (95% CI: 0.50, 1.00)]. Analytical approaches to address bias from more frequent prostate-specific antigen screening among aspirin users did not yield different conclusions. We observed reductions in the risk of high-grade and lethal prostate cancer associated with higher doses of aspirin, but not with greater frequency or duration, in a large, prospective cohort of health professionals. Our data support earlier observations of modest inverse associations with advanced prostate cancer.

Aberrant cytoplasmic expression of p63 and prostate cancer mortality

Protein expression of p63 is used to differentiate prostate cancer from benign mimickers. Recent studies suggest that it may also distinguish aggressive prostate cancer with down-regulated expression occurring in men with more advanced disease. We conducted a prospective study among 298 men ages 51 to 84 years who were diagnosed with prostate cancer in the Physicians' Health Study in 1983 to 2004 and whose tissue was available for immunohistochemical staining. We used Cox proportional hazards regression to evaluate the association of p63 protein expression with fatal prostate cancer. We correlated p63 expression with tumor cell proliferation (Ki-67) and apoptosis (TUNEL staining). The predominant location of tumor p63 staining occurred in the cytoplasm, an uncommon departure from the strong nuclear staining usually observed in nonneoplastic basal cells. Increasing expression of cytoplasmic p63 (tertiles) was associated with prostate cancer mortality (n = 19 deaths); the hazard ratios (95% confidence intervals) were 1.0 (reference), 4.0 (0.9-18.9), and 5.9 (1.3-27.5; P(trend) = 0.03). The positive trend remained significant (P = 0.047) after multivariable adjustment for age, year of diagnosis, and Gleason score. Higher tertiles of cytoplasmic p63 were also associated with reduced levels of apoptosis (P(trend) = 0.0408) and increased cellular proliferation (P(trend) = 0.0026). We found aberrant expression of p63 in the cytoplasm to be associated with increased prostate cancer-specific mortality up to 20 years after diagnosis. The mislocalized expression was associated with reduced apoptosis and higher proliferative activity and may suggest an oncogenic role in prostate cancer progression and survival.

Case-control studies of the efficacy of cancer screening: overcoming bias from nonrandom patterns of screening

A case-control study of the efficacy of cancer screening, like any other case-control study, must deal with potential confounding. There are 2 categories of confounding variables that pose special problems for studies of screening: (1) age and calendar time resulting from different temporal distributions of screening between cases and controls irrespective of whether the screening test leads to a reduction in mortality; and (2) the administration of other screening tests for the cancer in question when it is not clear whether the result of the other test had a bearing on the decision to order the test under study. We describe circumstances in which confounding from these sources can be dealt with satisfactorily by means of restriction or adjustment, and other circumstances in which it cannot.

Recreational physical activity and endometrioma risk

Endometriosis, defined by implantation of endometrial tissue outside the uterus, is commonly found on the ovaries and is characterized by a range of symptoms and severity, including chronic pelvic pain and infertility. The role of modifiable exogenous factors such as exercise in the development of this disease is not well understood. The authors conducted a 1990-1994 case-control study (77 cases, 735 controls) to evaluate the risk of cystic ovarian endometriosis (endometrioma) associated with recreational physical activity among females aged 18-39 years enrolled in the Group Health Cooperative of Puget Sound, Washington. Physical activity was evaluated according to its duration, frequency, and intensity during two periods of exposure: 2 years prior to the reference date and at ages 12-21 years. Women who reported frequent, high-intensity activity during the 2 years prior to the reference date had a 76% reduced endometrioma risk (odds ratio = 0.24, 95% confidence interval: 0.08, 0.71) compared with women who engaged in no high-intensity activity. A nonsignificant 53% reduction in risk was observed for women who reported such activity at ages 12-21 years (odds ratio = 0.47, 95% confidence interval: 0.18, 2.23). Activities of lower intensity, frequency, and duration were not associated with a woman's risk of endometrioma.

Family history of cancer and risk of esophageal and gastric cancers in the United States

The worldwide rates for histology- and subsite-specific types of esophageal and gastric cancer reveal strikingly divergent patterns. The contribution of environmental and genetic factors has been explored in several high-incidence areas, but data on genetic influences are scarce for Western countries. Using data from a multicenter, population-based, case-control study on 1,143 cases and 695 controls in the United States, we evaluated whether a family history of digestive or other cancers was associated with an increased risk of esophageal adenocarcinoma (n = 293), esophageal squamous cell carcinoma (n = 221), gastric cardia adenocarcinoma (n = 261) or non-cardia gastric adenocarcinoma (n = 368). After adjusting for other risk factors, individuals reporting a family history of digestive cancers experienced no increased risk of either type of esophageal cancer but they were prone to adenocarcinomas of the gastric cardia [odds ratio (OR) = 1.34, 95% confidence interval (CI) 0.91-1.97] and non-cardia segments (OR =1.46, 95% CI 1.03-2.08). This familial tendency, particularly for non-cardia gastric tumors, was largely explained by an association with family history of stomach cancer (OR = 2.52, 95% CI 1.50-4.23). In addition, family history of breast cancer was associated with increased risks of esophageal adenocarcinoma (OR = 1.74, 95% CI 1.07-2.83) and non-cardia gastric adenocarcinoma (OR = 1.76, 95% CI 1.09-2.82). Also seen were non-significant familial associations of esophageal squamous-cell cancer with prostate cancer as well as non-cardia gastric cancer with leukemia and brain tumors, though these relationships must be interpreted with caution. Our data point to the role of familial susceptibility to gastric cancer, but not to any form of esophageal cancer, in the United States.

Assessment of hospital and police ascertainment of automobile versus childhood pedestrian and bicyclist collisions

Information about automobile versus pedestrian or bicyclist collisions differ according to the source of collision ascertainment. Hospital records and police reports focus on different characteristics of a collision, which reflects differences in case finding as well as information regarding risk factors. Pedestrians and bicyclists 0-14 years of age who were involved in a motor vehicle collision in the city of Long Beach, CA, between January 1, 1992 and June 30, 1995, were included in the study. Police reports and medical records were used to identify cases. Police reports were found for 1,015 cases, and medical records identified 474 cases; 379 cases were common to both sources. A capture-recapture model was used to evaluate the degree of overlap between the two sources and to derive "ascertainment corrected" injury rates. The injury rate from combined sources was 333.5/100,000 children per year, the pedestrian injury rate was 210.6/100,000 children per year and the bicyclist injury rate was 122.9/100,000 children per year. The "ascertainment corrected" injury rate overall was 381.3/100,000 children per year, 233.0/100,000 for pedestrians and 153.9/100,000 children per year for bicyclists. Eighty percent of hospital-reported cases were captured in the police database, whereas only 37% of police-reported cases were captured by the hospital database. We found that hospital sources identified younger children, fewer bicyclists, more Asian and Hispanic children, and fewer African-American children when compared to police sources. For more comprehensive surveillance resulting in more accurate incidence rates and more complete information, it is better to use multiple sources of data.

A geographic analysis of motor vehicle collisions with child pedestrians in Long Beach, California: comparing intersection and midblock incident locations

OBJECTIVES

The purpose of this study was to use geographic information system (GIS) software to locate areas of high risk for child pedestrian-motor vehicle collisions in the city of Long Beach and to compare risk factors between midblock and intersection collisions.

METHODS

Children 0-14 years of age involved in a motor vehicle versus pedestrian collision that occurred on public roadways in Long Beach, CA, between 1 January 1992 and 30 June 1995, were identified retrospectively from police reports. The GIS software program, ArcView, was used for spatial analysis and distance calculations. chi2 Tests were used to compare the distribution of the characteristics between intersection and midblock collisions.

RESULTS

The average annual incident and fatality rate was 183.3/100,000 children/ year and 2.4/100,000 children/year, respectively. Children less than 5 years of age were significantly more likely to be hit at a midblock location while those aged 5-9 and 10-14 were more often hit at an intersection. Intersection collisions were more likely to occur on major arterials and local streets, and the driver to be the primary party at fault (p<0.001). While intersection incidents tended to occur further from the child's home (64.4%) the majority of midblock incidents (61.5%) occurred within 0.1 miles of the child's residence. For both midblock and intersection locations, pedestrian collisions tended to occur more frequently in those census tracts with a larger number of families per census tract-a measure of household crowding and density.

CONCLUSIONS

Future studies taking into consideration traffic volume and vehicle speed would be useful to focus prevention efforts such as environmental modifications, improving police enforcement, and educational efforts targeted at parents of younger children. As GIS illustrative spatial relationships continue to improve, relationships between pedestrian collision sites and other city landmarks can advance the study of pedestrian incidents.