Residential proximity to vines and risk of childhood embryonal tumours in France - GEOCAP case-control study, 2006-2013

BACKGROUND

Exposure to pesticides has been suggested as a potential risk factor for childhood embryonal tumour. The existing literature has mainly focused on parental occupational exposure and domestic use of pesticides, and is very limited for residential exposures to agricultural pesticides. The study aimed to test the hypothesis of an increased risk of embryonal tumour in children living close to viticultural plots, likely to be subject to frequent pesticide applications.

METHODS

The study is part of the French national registry-based GEOCAP program. We included 2761 cases of neuroblastoma, retinoblastoma, Wilms tumour and rhabdomyosarcoma diagnosed before the age of 15 years in the 2006-2013 period, and 40,196 controls representative of the same age population during this period. Indicators of proximity to vines, the presence of vines and viticulture density within 1000 m of the geocoded addresses of residence, were evaluated combining three sources of data on agricultural land use in a geographic information system. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regressions and carried out several sensitivity analyses to test the stability of the results.

RESULTS

Approximately 10% of the controls lived within 1000 m of vines, with regional variations ranging from <1% to 38%. We observed a 5% increase in the risk of neuroblastoma for a 10% increase in viticulture density (OR = 1.05, 95% CI: 0.98-1.13), with a regional heterogeneity. The indicators of proximity to vines were not associated with the other non-CNS embryonal tumours.

CONCLUSION

The study showed a slight increase in the risk of neuroblastoma in children living close to vines, suggesting that residential exposure to agricultural pesticides may be involved in the occurrence of these tumours.

Fertility and prognosis assessment between bleomycin/etoposide/cisplatin and paclitaxel/carboplatin chemotherapy regimens in the conservative treatment of malignant ovarian germ cell tumors: a multicenter and retrospective study

OBJECTIVE

To evaluate the impact of bleomycin/etoposide/cisplatin (BEP) and paclitaxel/carboplatin (PC) chemotherapy regimens on the fertility and prognostic outcomes in malignant ovarian germ cell tumor (MOGCT) patients who underwent fertility-sparing surgery (FSS).

METHODS

A propensity score matching algorithm was performed between the BEP and PC groups. The χ² test and the Kaplan-Meier method were used to compare the fertility outcome, disease-free survival (DFS) and overall survival (OS). The Cox proportional hazards regression analysis was used to identify risk factor of DFS.

RESULTS

We included 213 patients, 185 (86.9%) underwent BEP chemotherapy, and 28 (13.1%) underwent PC chemotherapy. The median age was 22 years (range, 8-44 years), and the median follow-up period was 63 months (range, 2-191 months). Fifty-one (29.3%) patients had a pregnancy plan, and 35 (85.4%) delivered successfully. In the before and after propensity score matching cohorts, there were no significant differences in spontaneous abortion, selective termination of pregnancy, during-pregnancy status, and live birth between the BEP and PC groups (p>0.05). Fourteen (6.6%) patients experienced recurrence, including 11 (5.9%) in the BEP group and 3 (10.7%) in the PC group. Four (1.9%) patients in the BEP group died. Kaplan-Meier analysis revealed no significant differences in DFS (p=0.328) and OS (p=0.446) between the BEP and PC groups, and the same survival results were observed in the after matching cohort.

CONCLUSION

The PC regimen is as safe as the BEP regimen for MOGCT patients with fertility preservation treatment, and no differences were observed in fertility and clinical prognosis.

Domestic use of pesticides during early periods of development and risk of testicular germ cell tumors in adulthood: a French nationwide case-control study

BACKGROUND

Testicular germ cell tumours (TGCT) are the most frequent cancers in young men in developed countries and their incidence rate has doubled worldwide over the past 40 years. Early life exposures to pesticides are suspected to increase TGCT risk. Our research aimed at estimating adult TGCT risk associated with parental domestic use of pesticides during early periods of child development.

METHODS

We conducted a case-control study of 304 TGCT cases, aged 18-45 years old, recruited in 20 French university hospitals, and 274 controls frequency-matched on hospital and birth year. Participants' mothers provided information on their domestic use of pesticides from 1 year before start of pregnancy to 1 year after their son's birth, for gardening activities, treatment of indoor plants, pets, wood and mold, and pest control. Odds ratios (OR) for TGCT (overall and by histological subtype) and 95% confidence intervals (CI) were estimated using conditional logistic regression.

RESULTS

Prevalence of reported domestic use of pesticides was 77.3% for insecticides, 15.9% for fungicides and 12.1% for herbicides. While no association was found for any use of insecticides (OR = 1.27, CI = 0.80-2.01) or herbicides (OR = 1.15, CI = 0.67-2.00), elevated risks of TGCT overall (OR = 1.73, CI = 1.04-2.87) and non-seminoma subtype (OR = 2.44, CI = 1.26-4.74) were observed for any use of fungicides. When specific purposes were examined, using fungicides and/or insecticides for woodwork (OR = 2.35, CI = 1.06-5.20) and using insecticides on cats and dogs (OR = 1.95, CI = 1.12-3.40) were associated with increased risk of non-seminoma subtype. We found no association for seminoma subtype.

CONCLUSIONS

Although recall bias may partially explain the elevated ORs, our study provides some evidence of a positive association between domestic use of pesticides during early periods of development, particularly fungicides and risk of adult TGCT and non-seminoma. Given the common domestic use of pesticides in France, further research on TGCT risk is warranted.

Exposure to ambient dichloromethane in pregnancy and infancy from industrial sources and childhood cancers in California

BACKGROUND

The incidence of childhood cancers has been increasing and environmental exposure to air toxics has been suggested as a possible risk factor. This study aims to explore ambient exposure to dichloromethane (methylene chloride).

METHODS

We frequency matched by birth year approximately 20 cancer-free controls identified from birth records to all childhood cancers ages 0-5 in the California Cancer Registry diagnosed from 1988 to 2012; i.e. 13,636 cases and a total of 270,673 controls. Information on industrial releases of dichloromethane within 3km of birth addresses was retrieved from mandatory industry reports to the EPA's Toxics Release Inventory (TRI). We derived exposure to dichloromethane within close vicinity of birth residences using several modeling techniques including unconditional logistic regression models with multiple buffer distances, inverse distance weighting, and quadratic decay models.

RESULTS

We observed elevated risks for germ cell tumors [Odds Ratio (OR): 1.52, 95% Confidence Interval (CI) 1.11, 2.08], particularly teratomas (OR: 2.08, 95% CI 1.38-3.13), and possible increased risk for acute myeloid leukemias (AML) (OR: 1.64, 95% CI 1.15-2.32 in the quadratic decay model). Risk estimates were similar in magnitude whether releases occurred in pregnancy or the child's first year of life.

CONCLUSION

Our findings suggest that exposure to industrial dichloromethane releases may be a risk factor for childhood germ cell tumors, teratomas, and possibly AML.

Male reproductive disorders, diseases, and costs of exposure to endocrine-disrupting chemicals in the European Union

INTRODUCTION

Increasing evidence suggests that endocrine-disrupting chemicals (EDCs) contribute to male reproductive diseases and disorders.

PURPOSE

To estimate the incidence/prevalence of selected male reproductive disorders/diseases and associated economic costs that can be reasonably attributed to specific EDC exposures in the European Union (EU).

METHODS

An expert panel evaluated evidence for probability of causation using the Intergovernmental Panel on Climate Change weight-of-evidence characterization. Exposure-response relationships and reference levels were evaluated, and biomarker data were organized from carefully identified studies from the peer-reviewed literature to represent European exposure and approximate burden of disease as it occurred in 2010. The cost-of-illness estimation utilized multiple peer-reviewed sources.

RESULTS

The expert panel identified low epidemiological and strong toxicological evidence for male infertility attributable to phthalate exposure, with a 40-69% probability of causing 618,000 additional assisted reproductive technology procedures, costing €4.71 billion annually. Low epidemiological and strong toxicological evidence was also identified for cryptorchidism due to prenatal polybrominated diphenyl ether exposure, resulting in a 40-69% probability that 4615 cases result, at a cost of €130 million (sensitivity analysis, €117-130 million). A much more modest (0-19%) probability of causation in testicular cancer by polybrominated diphenyl ethers was identified due to very low epidemiological and weak toxicological evidence, with 6830 potential cases annually and costs of €848 million annually (sensitivity analysis, €313-848 million). The panel assigned 40-69% probability of lower T concentrations in 55- to 64-year-old men due to phthalate exposure, with 24 800 associated deaths annually and lost economic productivity of €7.96 billion.

CONCLUSIONS

EDCs may contribute substantially to male reproductive disorders and diseases, with nearly €15 billion annual associated costs in the EU. These estimates represent only a few EDCs for which there were sufficient epidemiological studies and those with the highest probability of causation. These public health costs should be considered as the EU contemplates regulatory action on EDCs.

Studying the impact of early life exposures to pesticides on the risk of testicular germ cell tumors during adulthood (TESTIS project): study protocol

BACKGROUND

The incidence of testicular germ cell tumors (TGCT), the most common cancer in men aged 15 to 45 years, has doubled over the last 30 years in developed countries. Reasons remain unclear but a role of environmental factors, especially during critical periods of development, is strongly suspected. Reliable data on environmental exposure during this critical time period are sparse. Little is known on whether it could be a combined effect of early and later-life exposures.

METHODS/DESIGN

Our research aims to study the association between TGCT risk and pesticide exposures (domestic, occupational and environmental) during critical time periods of development and combined early and later-life exposures. The study design, developed during a 2-year pilot study, is a multicenter case-control study of 500 cases (ascertained through histology) and 1000 fertile/fecund controls recruited through 21 French 'Centres d'Etude et de Conservation des Œufs et de Sperme humain' (CECOS). Trained professional interviewers interview the subjects and their mothers by phone. Using a geographic information system developed and tested for application in this study design, environmental pesticides exposure assessment is based on life-time residential history. Occupational pesticides exposures are assessed by an industrial hygienist based on parents' occupations and tasks. Exposures during the prenatal period, early childhood and puberty are focused. A blood sample is collected from each participant to assess genetic polymorphisms known to be associated with TGCT risk, as well as to explore gene-environment interactions.

DISCUSSION

The results of our study will contribute to better understanding the causes of TGCT and the rapid increase of its incidence. We explore the effect of combined early and later-life pesticides exposure from multiple sources, as well as potential gene-environment interactions that have until now been rarely studied for TGCT. Our design allows future pooled studies and the bio-bank allows additional genetic or toxicological analyses.

Adolescents and young adults with a "rare" cancer: getting past semantics to optimal care for patients with germ cell tumors

Because the tumors of adolescence and young adulthood (AYA) are distinct from those that occur earlier and later in life, the most common tumors in this age group are termed “rare.” We offer a collaborative, cross-disciplinary, evidence-based approach, advocated and funded by civil society, to advance the field of germ cell tumor and potentially to apply to other rare AYA tumors.

[Testicular germ cell tumours and early exposures to pesticides: The TESTEPERA pilot study]

Testicular germ cell tumors (TGCT) represent the most frequent cancer in men aged between 15 and 45 years. Current hypotheses are focusing on environmental exposures occurring during prenatal periods. However, very few studies have explored intra-uterine environmental exposure related to TGCT. TESTEPERA is a pilot case-control study aiming to determine the effectiveness of different recruitment approaches in the French context and to verify our ability to collect relevant data on their prenatal periods. Between 2011 and 2012, 150 male subjects were contacted in the Rhône-Alpes region (58 cases from a cancer center and 92 controls from a regional maternity). Participation rate varied from 33% for cases diagnosed in 2008 vs 68% for cases diagnosed in 2010. Participation rate of controls varied depending on modalities of contact (13% for face-to-face recruitment; 0% for contact by phone only; 50% for face-to-face contact with phone reminder). Data collection allowed precise job identification and geolocation of subjects' addresses. Precision of geolocation was dependent upon the level of urbanization (p < 0.001) but not on the time period (p = 0.52). Our results support the feasibility of a case-control study focusing on the relation between TGCT and environmental pesticide exposures during early and later life.

Cisplatin induces resistance by triggering differentiation of testicular embryonal carcinoma cells

Although testicular germ cell tumors are generally quite responsive to treatment with cisplatin, a small fraction of them acquire resistance during therapy. Even when cisplatin treatment is successful the patient is often left with a residual teratoma at the site of the primary tumor suggesting that cisplatin may trigger differentiation in some tumors. Using the human embryonal carcinoma cell line NTera2/D1, we confirmed that exposure to the differentiating agent retinoic acid produced a reduction in pluripotency markers NANOG and POU5F1 (Oct3/4) and an acute concentration-dependent increase in resistance to both cisplatin and paclitaxel that reached as high as 18-fold for cisplatin and 61-fold for paclitaxel within four days. A two day exposure to cisplatin also produced a concentration-dependent decrease in the expression of the NANOG and POU5F1 and increased expression of three markers whose levels increase with differentiation including Nestin, SCG10 and Fibronectin. In parallel, exposure to cisplatin induced up to 6.2-fold resistance to itself and 104-fold resistance to paclitaxel. Paclitaxel did not induce differentiation or resistance to either itself or cisplatin. Neither retinoic acid nor cisplatin induced resistance in cervical or prostate cancer cell lines or other germ cell tumor lines in which they failed to alter the expression of NANOG and POU5F1. Forced expression of NANOG prevented the induction of resistance to cisplatin by retinoic acid. We conclude that cisplatin can acutely induce resistance to itself and paclitaxel by triggering a differentiation response in pluripotent germ cell tumor cells.

Environment, testicular dysgenesis and carcinoma in situ testis

The testicular dysgenesis syndrome (TDS) hypothesis proposes that a proportion of the male reproductive disorders-cryptorchidism, hypospadias, infertility and testicular cancer-may be symptoms of one underlying developmental disease, TDS, which is most likely a result of disturbed gonadal development in the embryo. TDS may be caused by genetic factors, environmental/life-style factors, or a combination of both. Some rare disorders of sex development of genetic origin are among the best-known examples of severe TDS. Among the environmental and life-style factors that are suspected to influence the hormonal milieu of the developing gonad are the endocrine disrupters. A prenatal exposure to commonly used chemicals, e.g. phthalates, may result in a TDS-like phenotype in rats. Currently, this animal model is the best model for TDS. In humans the situation is much more complex, and TDS exists in a wide range of phenotypes: from the mildest and most common form, in which impaired spermatogenesis is the only symptom, to the most severe cases, in which the patient may develop testicular cancer. It is of great importance that clinicians in different specialties treating patients with TDS are aware of the association between the different symptoms.

Reproductive dysgenesis in wildlife: a comparative view

Abnormal reproductive development in males has been linked to environmental contaminant exposure in a wide variety of vertebrates. These include humans, rodent models, and a large number of comparative wildlife species. In human males, abnormal reproductive development can manifest as a suite of symptoms, described collectively as testicular dysgenesis syndrome (TDS). TDS is also described as demasculinization or feminization of the male phenotype. The suite includes cryptorchidism, in situ germ cell carcinoma of the testis and overt testicular cancer, reduced semen quality, and hypospadias. In this paper, we review examples of TDS among comparative species. Wildlife exposed to environmental contaminants are susceptible to some of the same developmental abnormalities and subsequent symptoms as those seen in human males with TDS. There are additional end points, which are also discussed. In some cases, the symptoms are more severe than those normally seen in humans with TDS (i.e. oocytes developing within the testis) because some non-mammalian species exhibit greater innate reproductive plasticity, and are thus more easily feminized. Based on our review, we present an approach regarding the ontogeny of TDS. Namely, we suggest that male susceptibility to the androgynizing influences of environmental contaminants originates in the sexually undifferentiated embryo, which, in almost all species, including humans, consists of bipotential reproductive tissues. These tissues can develop as either male or female and their ultimate direction depends on the environment in which they develop.

Parental occupational exposure to pesticides and childhood germ-cell tumors

In a recently completed US case-control study (Children's Oncology Group, 1993-2001) with 253 cases and 394 controls, the authors investigated the association between parental occupational exposure to pesticides and risk of childhood germ-cell tumors. Information on occupational pesticide exposure was collected using job-specific module questionnaires and assessed by an experienced industrial hygienist. Odds ratios for childhood germ-cell tumors associated with maternal exposures before pregnancy, during pregnancy, and after the birth of the index child were 1.0 (95% confidence interval (CI): 0.8, 1.4), 1.1 (95% CI: 0.7, 1.6), and 1.3 (95% CI: 0.9, 1.8), respectively. Paternal exposures before pregnancy, during pregnancy, and after the birth of the index child were not related to germ-cell tumors (odds ratios (ORs) were 0.9 (95% CI: 0.7, 1.2), 0.8 (95% CI: 0.5, 1.2), and 0.8 (95% CI: 0.5, 1.3), respectively). When both parents had ever been occupationally exposed to pesticides before the index pregnancy, the odds ratio was 0.8 (95% CI: 0.4, 1.3). Subgroup analyses showed a positive association between maternal exposure to herbicides during the postnatal period and risk of germ-cell tumors in girls (OR = 2.3, 95% CI: 1.0, 5.2) and an inverse association between paternal exposure to pesticides during the index pregnancy and germ-cell tumors in boys (OR = 0.2, 95% CI: 0.1, 1.0). This study did not provide strong evidence supporting a relation between parental pesticide exposure in the workplace and risk of germ-cell tumors among offspring.

Occupational exposure to polyvinyl chloride as a risk factor for testicular cancer evaluated in a case-control study

Occupational exposures were assessed in a case-control study on testicular cancer using self-administered questionnaires. In total, answers were obtained for 148 (91%) cases and 315 (87%) controls. Of the cases, 101 had seminoma and 47 had embryonal testicular cancer. An increased odds ratio (OR) was found for exposure to polyvinyl chloride (PVC) yielding an OR of 6.6 (95% confidence interval, 1.4-32). The risk increased further if cases with self-reported cryptorchidism or orchitis were excluded. Six of the 7 exposed cases had seminoma. Exposure to other types of plastics did not significantly increase the risk of testicular cancer.

Gynecologic tumors in tamoxifen-treated women with breast cancer

OBJECTIVES

To present six additional cases of gynecologic tumors in tamoxifen-treated breast cancer patients, review the literature, and recommend measures for surveillance.

METHODS

The hospital and office records of patients treated with tamoxifen at the University of Kansas Medical Center and Research Medical Center were analyzed. A comprehensive review of tamoxifen in the English and European literature was performed using MEDLINE and the bibliographies of various articles.

RESULTS

From 1985-1992 at our institutions, six tamoxifen-treated breast cancer patients developed gynecologic tumors: three endometrial adenocarcinomas, a mixed müllerian sarcoma, a fallopian tube carcinoma with adenofibroma of the endometrium, and recurrent hyperplastic endometrial polyps. The literature contained 61 cases of adenocarcinoma of the endometrium and possibly four cases of uterine sarcomas in tamoxifen-treated breast cancer patients. The number of gynecologic malignancies reported is now 70. In 35 of the patients, the mean age (+/- standard deviation) was 63.9 +/- 12.0 years, and 61 of 66 patients (92.4%) were postmenopausal. Of the endometrial adenocarcinomas, 25 of 27 (92.6%) were stage I, and 11 of 27 (40.7%) were grade 1. The dose of tamoxifen was 20 mg/day in 15 (23.4%), 30 mg/day in 11 (17.2%), and 40 mg or higher in 38 (59.4%); 57% were treated with tamoxifen for less than 2 years.

CONCLUSIONS

Tamoxifen is a safe and reliable treatment of breast cancer, but data suggest an association with endometrial cancer. We propose close monitoring of patients taking tamoxifen and prompt evaluation of any uterine bleeding or pelvic complaint.

High-grade endometrial carcinoma in tamoxifen-treated breast cancer patients

PURPOSE

Several reports have associated tamoxifen administration with endometrial carcinoma. A retrospective study of the histologic features of uterine cancer in patients with a history of breast carcinoma was undertaken to determine the effect of treatment with tamoxifen.

MATERIALS AND METHODS

A computer search of the Yale-New Haven Hospital Tumor Registry from 1980 to 1990 identified 53 patients with a history of breast carcinoma who subsequently developed a malignant tumor of the uterine corpus.

RESULTS

Fifteen patients received tamoxifen for breast carcinoma and 38 did not. The mean ages of the two groups were not significantly different. The mean interval between detection of breast and endometrial cancers was 5 years in the tamoxifen group and 12 years in the nontreated group (P = .0023). Sixty-seven percent of patients in the tamoxifen group had poorly differentiated endometrioid carcinomas (including adenosquamous carcinoma) or carcinomas associated with poor outcome (eg, uterine papillary serous carcinoma, clear-cell carcinoma, or mixed müllerian tumor), as compared with 24% in the nontreated group (P = .03). Patients in the tamoxifen group were much more likely to die of endometrial cancer (33.3% v 2.6% of the nontreated group, P = .005).

CONCLUSION

From this retrospective study, it appears that women receiving tamoxifen as treatment for breast cancer who subsequently develop uterine cancer are at risk for high-grade endometrial cancers that have a poor prognosis. These findings also indicate that tamoxifen-associated uterine cancers may have a different basis from those associated with steroidal estrogen treatment.

[Immunohistochemical studies of recessive oncogene p53 and N-myc oncogene expression in 7, 12 dimethylbenz (a) anthracene-induced rat ovarian tumors]

In the present study, the expressions of p53 and N-myc gene were analyzed immunohistochemically in rat ovarian tumors induced by 7,12 dimethylbenz (a) anthracene (DMBA). 1) p53 could be seen in the nucleolei of tumor cells. The positive rates were: adenomas 17%, adenocarcinomas 37%, sarcomas 0%, mixed müllerian tumor 0% and epidermal cysts 100%. Neither the serial-allografted tumor nor DMBA-OC-1 was positive. 2) N-myc could be seen in the cytoplasm and perinuclear cytoplasm of tumor cells. The positive rates were: adenomas 33%, adenocarcinomas 77%, sarcomas 100%, mixed müllerian tumors 100% and epidermal cysts 100%. Both the serial-allografted tumor and DMBA-OC-1 were positive. 3) The positive rates in both p53 and p21 were: adenocarcinoma 20% and epidermal cysts 100%. The positive rates in both N-myc and p21 at the were: adenoma 17%, adenocarcinoma 50%, sarcoma 33%. Both the serial-allografted tumor and DMBA-OC-1 were positive. Only two cases were positive for p53, N-myc and p21. p53 was detected in most of the adenomas. 4) The positive rate for both N-myc and p21 was higher than that for both p53 and p21. This was similar to other reports. The results suggested that p53 plays a role in precancerous tumor as a recessive oncogene. It was supposed that tumors with N-myc gene expression were had malignant growth characteristics.

Increased fucosylation of high-molecular-weight glycoproteins accompanies retinoic-acid-induced differentiation of F-9 embryonal carcinoma cells

Retinoic acid (RA) treatment of F-9 embryonal carcinoma cells resulted in cell flattening and increased production of laminin B1 chain, both indicating differentiation to endoderm-like cells. In addition, RA caused a time- and dose-dependent decrease in growth rate in monolayer culture and a dose-dependent decrease in the ability of the cells to form colonies in soft agarose. Differentiation was accompanied by an increase in the fucosylation of specific high-molecular-weight cellular and cell-surface glycoproteins. The fucosylation of glycoproteins of Mr 175,000 (gp175), 250,000 (gp250), and 400,000 (gp400) increased as early as 24 hr after the addition of 5 x 10(-6) M RA to the culture medium. These changes preceded both growth inhibition and the induction of laminin B1 expression, which were detected 48 to 72 hr after addition of RA. The increased fucosylation of these glycoproteins showed a distinct dose-response relationship. Both gp175 and gp250 showed the greatest increase in fucosylation at 10(-5) M, which was also the dose at which RA induced laminin maximally, while the fucosylation of gp400 was greatest at 10(-8) M RA and declined at higher concentrations. The overall synthesis of large fucosylated glycopeptides decreased in RA-treated cells, in spite of the increases in the fucosylation of specific cellular glycoproteins. RA-induced differentiation of F-9 cells was also accompanied by a time- and dose-dependent increase in fucosyltransferase activity. Although the functions of these glycoproteins are not currently known, the early increase in their fucosylation can be considered as a marker of differentiation in this system.

Primitive neuroectodermal tumor presenting as a delayed sequela to cranial irradiation and intrathecal methotrexate

A patient developed a primitive neuroectodermal tumor (PNET) many years after therapeutic cerebral radiation and methotrexate treatment for leukemia. The differential radiologic and histologic diagnoses, as well as the possible co-oncogenic effects of radiation and methotrexate, are evaluated.

Germ cell tumors of the testicle among aircraft repairmen

A cluster of testicular germ cell tumors occurred among 3 of 153 white men who worked in a shop engaged in repair of exterior surfaces and electrical components of the airframes of F4 Phantom Jet aircraft. Evaluation of an occupationally identical shop at a second F4 rework facility at which there had been no previous reports of excess neoplasms revealed 4 additional men with a history of testicular germ cell tumors (p less than 0.01, Poisson, compared to the expected number of cases based on national incidence rates). Our investigation raises but does not prove a hypothesis of association between subsequent development of testicular germ cell cancer and history of extensive exposure to a mixture containing dimethylformamide, which had been used in F4 repair work at these facilities in the 1960s and 1970s. This represents the first report of 2 corresponding mini-epidemics of testicular tumors among workers in occupationally identical industrial settings.

Testicular germ cell tumors after clomiphene therapy for subfertility

The stimulatory effect of low doses of clomiphene citrate on the human male gonad is accepted widely. We used 25 mg. clomiphene daily for 3 weeks, with 1 week of rest, for 6 to 12 months in 650 oligospermic men without increased serum levels of follicle-stimulating hormone (less than 20 IU/l.). Unilateral testicular neoplasm developed in 2 subjects. Although a definite cause-and-effect relationship between treatment and tumor development cannot be assigned the possible risk of tumor development in men undergoing long-term clomiphene treatment is suggested. Since clomiphene administration or gonadotropin treatment might enhance tumor development in men, patients at risk undergoing such therapy should be examined frequently and when a testicle enlarges a malignant tumor must be ruled out.

Immunohistochemical studies on cellular character of microtumors induced by ethylnitrosourea in the rat brain utilizing anti-Leu 7 and anti-glial fibrillary acidic protein antibodies

To clarify the chronologic changes in the cellular morphology of ENU-induced rat brain tumors, microtumors in the early stage were examined immunohistochemically in comparison with macrotumors in the advanced stage. The tumor cells composing microtumors were negative for glial fibrillary acidic protein (GFAP), a specific marker of astrocytic cells, and Leu 7, a marker of oligodendrocytes, while cells of macrotumors were positive for either GFAP or Leu 7, showing characteristics of mature glial cells. The results suggested that the small round cells in the early developmental stage, generally thought to resemble mature oligodendrocytes, are not differentiated oligodendrocytes or astrocytes.

Tissue differentiation and susceptibility to embryonal tumor induction by ethylnitrosourea in the opossum

Opossums (Didelphis virginiana Kerr) exposed to 100 mg ENU/kg in single or incremental doses early in postnatal life developed a spectrum of epithelial and mesenchymal neoplasms including several types of embryonal neoplasms not previously induced in laboratory animals. A correlation was apparent to a varying degree between susceptibility to tumor induction and the state of morphologic maturation of the presumed target tissues at the light microscopic level for embryonal tumors of the eye, kidney, and brain. The susceptibility of the opossum eye to an ENU-induced intraocular teratoid medulloepithelioma extended over the period from 1 to between 3 and 4 weeks of age and was correlated with the differentiation of the apparent target cell, the nonpigmented ciliary epithelium of the pars ciliaris retinae. Induction of nephroblastomas was correlated with the presence in the kidney of stem cells (metanephric blastema) through the period from birth to between 6 and 8 weeks of age. Although susceptibility of the opossum brain to ENU induction of gangliogliomas was correlated with the state of differentiation of the germinal matrix from birth to 56 days of age, induction of these tumors was essentially limited to the 1st week postpartum. No definite correlation between vulnerability to tumor induction and tissue maturation was evident for a tumor of the jaw (ameloblastoma) with presumed origin from embryonic dental remnants. Our results indicated that the opossium early in postnatal life is a useful model for the induction and characterization of certain of the major dysontogenetic tumors, which have been difficult or impossible to reproduce in the traditional laboratory species.

Effect of N-(3,5-dichlorophenyl)succinimide on the histological pattern and incidence of kidney tumors induced by streptozotocin rats

The effect of the nephrotoxic substance, N-(3,5-dichlorophenyl)succinimide, on the histological pattern and incidence of kidney tumors induced by streptozotocin in rats was studied. In groups administered streptozotocin alone or in combination with nicotinamide, the histological pattern and the incidence of kidney tumors in rats were similar; renal cell tumors developed in 1 of 9 rats (11.1%) and in 2 of 17 rats (11.8%), respectively. However, post-treatment with N-(3,5-dichlorophenyl)succinimide increased the induction of epithelial tumors by streptozotocin, and embryonal cell tumors were also induced nearly as frequently. Administration of nicotinamide alone did not result in the development of kidney tumors.

[Transplacental oncogenic effect of ethylnitrosourea in rabbits (author's transl)]

50 mg/kg ethylnitrosourea (ENU) per dose, diluted in a 0.9%NaCl/1%NaH2PO4 solution (pH 6.2) were administered intravenously to three pregnant rabbits. The injections were carried out on the following days of gestation: 21., 26., and 30./21., 25., and 31./22., 25., and 30. From the total offspring (22), 16 rabbits could be raised. In 12 animals, kidney tumours were observed after a latent period of 2--2 1/2 years. The induced tumours are generally composed of both epithelial and mesenchymal tissue elements. Two tumours of the series are of a pure epithelial or a pure mesenchymal nature respectively. In most of the mixed tumours, classified as Adenocarcino-Sarcomas (10), the epithelial and mesenchymal elements are closely integrated, sometimes one component predominated over the other one. Histologically the ENU-induced mixed tumours of kidney in rabbits and the "dysontogenetic" kidney tumours of children (WILMS) show comparable structural characteristics.