Anxiety as a predictor of the age of initiation of tobacco and cannabis use in adolescents and young adults.

BACKGROUND: Previous research has shown important links between anxiety and the use of tobacco and cannabis. However, it remains unclear whether anxiety leads youth to start using tobacco and cannabis at an earlier age. METHODS: Data were drawn from Texas Adolescent Tobacco and Marketing Surveillance System for the years 2019-2021(Waves 9-14). Participants were in 10th-grade, 12th-grade, and two years post-high school at baseline. The outcomes were the age of first use of cigarettes, e-cigarettes, and cannabis. Interval-censoring Cox proportional hazards models were fit to examine the differences in the estimated age of initiation of tobacco and cannabis use by anxiety. RESULTS: Among the 10th-grade cohort, participants with anxiety had an increased risk of an earlier age of cigarette [AHR = 2.29(1.63-3.23)], e-cigarette [AHR = 1.53(1.17-2.00)], and cannabis [AHR = 1.59(1.23-2.05)] initiation. Among the 12th-grade cohort, participants with anxiety had an increased risk of an earlier age of cigarette [AHR = 1.52(1.21-1.90), e-cigarette [1.25(1.01-1.60)] and cannabis [AHR = 1.35(1.09-1.67] initiation. Among the post-high school cohort, the only significant association found was for cannabis initiation [AHR = 1.33(1.11-1.58). Between ages 18-to-19 years in the 10th-grade cohort, and between ages 20-21 years in the 12th-grade cohort, cumulative incidence of each of the three outcomes initiation doubled among anxious youth. CONCLUSIONS: This study's findings show that anxiety symptoms can increase the risk of substance use initiation at an earlier age, especially among the youngest adolescent cohort (∼15-to-16-year-olds). These findings highlight the importance of early screening and treatment of anxiety symptoms as a preventive measure to delay or prevent the onset of substance use initiation.

Depressive symptoms and the age of initiation of tobacco and marijuana use among adolescents and young adults.

BACKGROUND: Studies have demonstrated important associations between depressive symptoms and tobacco and marijuana use. However, to date, it is unknown if depressive symptoms predispose youth to tobacco and marijuana use at earlier ages over time. METHODS: Data from the Texas Adolescent Tobacco and Marketing Surveillance System (TATAMS) for the years 2019-2021 (Waves 9-14) were used. Eligible samples include individuals who had never used cigarette (n=1776), e-cigarette (n=1353), or marijuana (n=1505) at basline and had complete data on covariates. Interval-censoring survival analysis was used to examine the differences in the estimated age of first use of cigarettes, e-cigarettes, and marijuana by depressive symptoms. RESULTS: 10th-grade cohort participants with depressive symptoms had increased risk of earlier age of first use of cigarette [AHR=1.45; 95% CI=1.02-2.04)], e-cigarette [AHR=1.65(1.27-2.15)], and marijuana [AHR=1.56(1.20-2.01)]. 12th-grade cohort participants with depressive symptoms had increased risk of earlier age of first use of cigarette [AHR=1.41(1.11-1.82), e-cigarette [AHR=1.35(1.10-1.87)] and marijuana [AHR=1.25(1.01-1.55)]. However, among the two-year post-high school cohort, depressive symptoms predicted the age of first use of marijuana only [AHR=1.34(1.13-1.60)]. Between ages 18-to-20 years, the estimated cumulative incidence of initiation almost doubled for all three products among depressive participants in 10th and 12th-grade cohorts. CONCLUSIONS: Among 10th-grade, 12th-grade, and 2-year post-HS students, those with depressive symptoms initiate tobacco and marijuana use at earlier ages than peers without depressive symptoms. Early screening and management of depressive symptoms among adolescents and young adults may be a promising target for preventing or delaying the age of first use of substance use.

The Association Between Tobacco and Cannabis Use and the Age of Onset of Depression and Anxiety Symptoms: Among Adolescents and Young Adults.

INTRODUCTION: No studies have prospectively explored the association between the use of tobacco or cannabis use and the age of onset of depressive or anxiety symptoms, and no studies have identified the peak ages and ranges of onset of these symptoms among tobacco and/or cannabis users. AIMS AND METHODS: This is a secondary analysis of Texas Adolescent Tobacco and Marketing Surveillance System data, waves 9-14 (2019-20121). Participants were in 10th grade, 12th grade, and 2 years post-high school (HS) at baseline (wave 9). Interval-censoring multivariable Cox proportional hazards models were fit to assess differences in the estimated age of onset of depression and anxiety by tobacco and cannabis use while adjusting for covariates. RESULTS: We found that lifetime or ever cigarette, e-cigarette, and cannabis use had an increased risk of an earlier age of onset of depressive and anxiety symptoms across the three cohorts, and the youngest cohort was the most differentially impacted by substance use. Between ages 18 to 19 years in the 10th-grade cohort, between ages 20 to 21 years in the 12th-grade cohort, and between ages 22 to 23 years in the post-HS cohort, the estimated hazard function (or cumulative incidence) for reporting depressive and anxiety symptoms almost doubled among lifetime cigarette, e-cigarette, and cannabis users. CONCLUSIONS: Tobacco and cannabis users should be screened for mental health problems at an earlier age, especially those aged 18 years and younger, and provided with age- and culturally appropriate resources to prevent or delay the onset of anxiety and/or depression symptoms. IMPLICATIONS: The study's findings indicate that tobacco and cannabis use is directly linked to the early onset of depressive and anxiety symptoms among youth. This highlights the significance of early screening and substance use interventions, particularly for youth aged 18 years and younger, as they are disproportionately affected by both substance use and mental health problems. School-based interventions that are age- and culturally appropriate hold promise as they enable youth to seek professional help early, and in a supportive environment. Intervening early in substance shows promise in reducing the likelihood of developing mental health problems at a young age.

Association of tobacco and marijuana use with symptoms of depression and anxiety among adolescents and young adults in Texas.

INTRODUCTION: Young people with depression and/or anxiety may self-medicate with tobacco or tobacco with marijuana to reduce their symptoms. This study sought to differentiate between the use of tobacco products as intended and tobacco products modified to accommodate marijuana, and to explore their relationships with symptoms of depression and anxiety among youth and young adults. METHODS: The study is a secondary analysis of Wave 9 (Spring 2019) data from the Texas Adolescent Tobacco and Marketing Surveillance (TATAMS) (n=2439, N=274030). Anxiety and major depressive symptoms were measured by GAD-7 and PHQ-9, respectively. RESULTS: The odds of reporting current use of e-cigarettes without marijuana (adjusted prevalence odds ratio, APOR=2.34; 95% CI: 1.30-4.21, p=0.005) and current use of combustible tobacco without marijuana (APOR=2.99; 95% CI: 1.26-7.09, p=0.014) were significantly higher among those who reported depression/anxiety comorbidity compared to those who reported no symptoms of major depressive symptoms (MDS), anxiety or comorbidity. The odds of reporting ever use of e-cigarettes with marijuana (APOR=3.68; 95% CI: 1.69- 8.00, p=0.001), current use of e-cigarettes with marijuana (APOR=2.76; 95% CI: 1.28-5.97, p=0.01) and ever use of combustible tobacco with marijuana (APOR=3.99; 95% CI: 1.66-9.58, p=0.002) were significantly higher among those reporting only MDS compared to those who reported no symptoms of MDS, anxiety or comorbidity. CONCLUSIONS: The study findings can have implications for intervention planning, as interventions need to address marijuana and nicotine use in tobacco products and address anxiety and depression.

Emotional symptoms and sensation seeking: Implications for tobacco interventions for youth and young adults.

INTRODUCTION: Although emotional symptoms and sensation seeking are recognized as important risk factors for tobacco use among youth and young adults, to date, their joint influence on tobacco use has not been examined. METHODS: Data used in this study are from the Texas Adolescent Tobacco and Marketing Surveillance study, a population-based cohort. At baseline, in 2014, participants were in the 10th grade. Mixed-effects logistic regression models examined associations between emotional symptoms and sensation seeking in 2014 and odds of past 30-day cigarette and e-cigarette use in 2018. Interactions between emotional symptoms and sensation seeking were examined to assess whether one modifies the effect of the other on cigarette and e-cigarette use. RESULTS: After adjusting for age, sex, race/ethnicity, school type, and ever use of cigarettes or e-cigarettes at baseline, adolescents with high emotional symptoms (AORcig=1.97; 95% CI:1.07-3.60, and AORe-cig=1.68; 95% CI: 1.06-2.66) and with high sensation seeking tendencies (AORcig=2.05; 95% CI: 1.03-4.10, and AORe-cig=1.68; 95% CI: 1.02-2.76) had significantly higher odds of past 30-day cigarette and e-cigarette use four years later compared to adolescents with low emotional symptoms and low sensation seeking tendencies. The interaction was significant (p=0.01) for e-cigarette use only; among low sensation seekers, adolescents who reported high levels of emotional symptoms were at increased risk for past 30-day use (AORe-cig=3.43; 95% CI: 1.38-8.51), and among adolescents with low emotional symptoms, high sensation seekers were at increased for risk for past 30-day use (AORe-cig=3.50; 95% CI: 1.54-7.91). CONCLUSIONS: It is important for tobacco use prevention programs to consider both behavioral risk factors - sensation seeking and emotional symptoms - in an integrative way, to target high risk subgroups and thereby increase the efficacy of existing effective intervention strategies in order to curb tobacco use among youth and young adults.

Are comorbidities associated with long-term survival of lung cancer? A population-based cohort study from French cancer registries.

BACKGROUND: Survival rates of lung cancer remains poor and the impact of comorbidities on the prognosis is discussed. The objective of this study was to assess if the Charlson Comorbidity Index (CCI) was associated with 8-year survival rates by histological type. METHODS: A cohort study was conducted using randomly selected cases from 10 French cancer registries. Net survival rates were computed using the Pohar-Perme estimator of the net cumulative rate. Three Cox models were independently built for adenocarcinomas, squamous cell and small cell cancers to estimate prognostic factors including CCI grade. RESULTS: A total of 646 adenocarcinomas, 524 squamous cell and 233 small cell cancers were included in the analysis. The net 8-year survival rate ranged from 12.6% (95% CI: 9.8-15.4%) for adenocarcinomas and 13.4% (95% CI: 10.1-16.7%) for squamous cell carcinomas, to 3.7% (95% CI: 1.1-6.3%) for small cell cancers. Observed and net survival rates decreased for CCI grades ≥3 for all histological group considered. After adjustment for sex, age group, stage and diagnostic mode, CCI grades 1 (HR = 1.6 [95% CI: 1.1-2.3]), 2 (HR = 1.7 [95% CI: 1.1-2.7]) and ≥ 3 (HR = 2.7 [95% CI: 1.7-4.4]) were associated with lower survival rates only for small cell cancers. CONCLUSION: After adjustment for age, sex, stage and diagnostic mode, the presence of comorbidity based on CCI grades 1-2 and ≥ 3 was associated with lower survival rates for small cell cancers whereas no differences were observed for adenocarcinomas and squamous cell cancers.

Merkel cell carcinoma in France: a registries-based, comprehensive epidemiological survey.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare primary cutaneous neuroendocrine carcinoma. Owing to its low incidence, epidemiological data are scarce and have never been analysed in France to identify the main epidemiological trends. METHODS: Data from MCC patients diagnosed between 1998 and 2010 were obtained from 11 French cancer registries in the FRANCIM network. The main epidemiological characteristics of MCC were investigated between 2006 and 2010 because comprehensive data were only available for this period. The main focus was tumour incidence and mortality over time. RESULTS: Between 1998 and 2010, 562 cases of MCC were reported in the registries. From 2006 to 2010 (290 cases), European- and world-standardized incidence rates were 0.26 and 0.43 per 100,000 person-years in men and 0.24 and 0.38 per 100,000 person-years in women. MCC is more frequent in females in France (56.9%) with male/female ratio 1.1. Relative survival rates were 84%, 56% and 42% at one, three and 5 years, respectively. CONCLUSIONS: The incidence of MCC clearly increased over time in all areas under focus. The standardized incidence in France was comparable to the incidence observed in other countries for the same period, but French data are too recent to conclude on an increase in MCC incidence. Prognosis remains poor in all countries in which data are available.

Oral cancer characteristics in France: Descriptive epidemiology for early detection.

Despite the frequency and lethality of oral cancers in France, there are no detailed general population data regarding the characteristics of these patients to fuel the public health authorities' reflections about early detection policies. Thus, the objective of this study was to determine, in the general population, the characteristics of both patients and tumours at the time of the diagnosis. A high-resolution, population-based study using 13 French registries was conducted on 1089 tumours diagnosed in 2010. Men accounted for 75% of cases. The most frequent sites were tonsil (28.4%) and oral tongue (21.1%). The median age varied from 56.7 years for floor of mouth to 66.4 years for gum. The lesions were mainly diagnosed on pain and those diagnosed after routine clinical examination were scarce (2.6%). There were 65.5% stage III and IV at diagnosis. Oral tongue, floor of mouth and palate presented tumours less than 2cm only in 34 to 40% of cases. Advanced stage was associated with the presence of comorbidities, and tonsil or base of tongue topography. Stage was not associated with Département, deprivation index or gender. This study provided a picture of the characteristics of oral cancer patients and their tumours and showed that diagnoses are often made late, even for those tumours most easily accessible to direct visual and tactile examination. Nevertheless, it remains to define the target population of an early detection and to evaluate the benefit of such detection on the mortality rate.

Waiting time disparities in breast cancer diagnosis and treatment: a population-based study in France.

Waiting times are key indicators of a health's system performance, but are not routinely available in France. We studied waiting times for diagnosis and treatment according to patients' characteristics, tumours' characteristics and medical management options in a sample of 1494 breast cancers recorded in population-based registries. The median waiting time from the first imaging detection to the treatment initiation was 34 days. Older age, co-morbidity, smaller size of tumour, detection by organised screening, biopsy, increasing number of specimens removed, multidisciplinary consulting meetings and surgery as initial treatment were related to increased waiting times in multivariate models. Many of these factors were related to good practices guidelines. However, the strong influence of organised screening programme and the disparity of waiting times according to geographical areas were of concern. Better scheduling of diagnostic tests and treatment propositions should improve waiting times in the management of breast cancer in France.

[Prostate cancer management and factors associated with radical prostatectomy in France in 2001]. / Le cancer de la prostate en France en 2001: état des pratiques et facteurs associés à la réalisation d'une prostatectomie totale.

INTRODUCTION: Prostate cancer was the most common cancer in men in France in 2005, and the second cause of male death from cancer. In this study, we analyzed clinical characteristics of patients with prostate cancer diagnosed in France in 2001 with a focus on therapeutic management of localized prostate cancers. PATIENTS AND METHODS: A total of 2181 cases of prostate cancer diagnosed in 2001 from 11 French counties covered by a cancer registry were analyzed. A descriptive study of the clinical characteristics of patients was performed. Parameters studied included age, county, TNM stage, PSA value, Gleason score, D'Amico prognostic group, Charlson's comorbidity index and initial treatment modalities. For localized cancers, multivariate logistic regression analysis identified factors associated with radical prostatectomy. RESULTS: The proportion of localized prostate cancer (T1 or T2) was 86.6 %. The use of invasive curative treatment (radical prostatectomy and radiotherapy) was 58.4 % for localized cancers. Significant differences in therapeutic management were found between counties. Radical prostatectomy was associated with age at diagnosis, D'Amico prognostic group and the presence of comorbidities. CONCLUSIONS: Most of prostate cancers diagnosed in France in 2001 were clinically localized and were treated by invasive therapy. The consequences of these practices remain to be determined given the limited evolution of many prostate cancers and the frequency of adverse events related to invasive treatments.

A population-based study of adjuvant chemotherapy for stage-II and -III colon cancers.

BACKGROUND: Although clinical trials have demonstrated that adjuvant chemotherapy improves survival for stage-III colon cancer, the benefits remain controversial for stage-II lesions. The objective of the present study was to determine the extent to which adjuvant chemotherapy is used for patients with stage-II and -III colon cancers. METHODS: The study population comprised 1074 patients with stage-II and -III colon cancers diagnosed in 2000 in 12 French administrative districts and recorded in population-based cancer registries. Data were collected using a standardized procedure. RESULTS: Overall, 20.4% of patients with stage II and 61.9% with stage III received adjuvant chemotherapy. Age at diagnosis was the strongest determinant of chemotherapy. Among stage-II patients, those receiving chemotherapy decreased from 57.6% in patients aged or=85. The corresponding percentages with stage III were 93.6% and 1.4%. In multivariate analyses, other factors found to be independently and significantly associated with administration of adjuvant chemotherapy for stage II were extension of the cancer (stage IIA vs. stage IIB), clinical presentation (obstruction or perforation vs. uncomplicated cancer) and discussion of the case at a multidisciplinary case-review meeting. For stage III, apart from age, discussion of the case at a multidisciplinary meeting was the only factor independently associated with administration of chemotherapy. CONCLUSION: Adjuvant chemotherapy for stage-III colon cancer is used extensively for patients under 75 years of age. However, many elderly patients do not receive such treatment. On the other hand, a substantial percentage of stage-II colon cancer patients receive adjuvant chemotherapy despite its uncertain benefits.

Evolution of pleural cancers and malignant pleural mesothelioma incidence in France between 1980 and 2005.

The evolution of pleural cancers and malignant pleural mesothelioma incidence in France between 1980 and 2005 was analysed using data derived from the French network of cancer registries (FRANCIM) and the French National Mesothelioma Surveillance Program (PNSM). Mesothelioma proportions in pleural cancers were calculated by diagnosis year in the 1980-2000 period. Our results suggest that the incidences of pleural cancer and mesothelioma levelled off in French men since 2000 and continued to increase in French women. A decrease of the annual pleural cancer incidence average in men was noticed (-3.4% of annual rate of change) between 2000 and 2005. The proportion of pleural cancers that were mesothelioma was unchanged between 1980 and 2003 with an average of 86%. The age standardised incidence rate of pleural mesothelioma remained relatively stable between 1998 and 2005 with a slight falling trend. For women, the age standardised incidence rate of pleural cancers and mesothelioma increased during the period 1998-2005. Additionally, the proportion of pleural cancers that were mesothelioma increased during the same period of time. Finally, the increased trend observed in the incidence of pleural mesothelioma and cancers in women is credibly due to their under diagnosis in the 1980-1997 period. The comparison between the French incidence and the American and British ones shows that the decreasing trend in incidence of mesothelioma and pleural cancers in French men since 2000 is potentially associated with a lower amphibole consumption and by the implementation of safety regulations at work from 1977.

Spatial distribution of uranium and thorium in the surface soil around proposed uranium mining site at Lambapur and its vertical profile in the Nagarjuna Sagar Dam.

The understanding and evaluation of the possible interactions of various naturally occurring radionuclides in the world's third largest man-made dam, Nagarjuna Sagar located in Andhra Pradesh, India and built on river Krishna assumed significance with the finding of uranium deposits in locations near the dam. For the present work, surface soil samples from the mineralized area of Lambapur, Mallapuram, Peddagattu and sediment core samples from the Nagarjuna Sagar dam were analyzed for naturally occurring radionuclides namely uranium and thorium using gamma spectrometric technique. Also toxic elements lead and chromium were analysed by the Energy Dispersive X-ray Fluorescence Spectrometer (EDXRF) technique. Surface soil samples show a variation from 25 to 291 Bq/kg (2.02-23.5 mg/kg) for (238)U and 32-311 Bq/kg (7.9-76.9 mg/kg) for (232)Th. U/Th concentration ratio in surface soil samples ranged from 0.19 to 0.31 and was found comparable with the nation wise average of 0.26. The study of sediment core samples reflected higher U/Th concentration ratio of 0.30-0.33 in the bottom section of the core as compared to 0.22-0.25 in the upper section. The concentration ratio in the upper section of the core was similar to the ratio 0.23 found in the western Deccan Basalt region through which the river originates. A higher concentration of lead and chromium was observed in the upper section of the core compared to bottom section indicating the impact of river input on the geochemical character of dam sediment.

Cancer incidence and mortality in France over the period 1980-2005.

BACKGROUND: The objective of this study was to provide updated estimates of national trends in cancer incidence and mortality for France for 1980-2005. METHODS: Twenty-five cancer sites were analysed. Incidence data over the 1975-2003 period were collected from 17 registries working at the department level, covering 16% of the French population. Mortality data for 1975-2004 were provided by the Inserm. National incidence estimates were based on the use of mortality as a correlate of incidence, mortality being available at both department and national levels. Observed incidence and mortality data were modelled using an age-cohort approach, including an interaction term. Short-term predictions from that model gave estimates of new cancer cases and cancer deaths in 2005 for France. RESULTS: The number of new cancer cases in 2005 was approximately 320,000. This corresponds to an 89% increase since 1980. Demographic changes were responsible for almost half of that increase. The remainder was largely explained by increases in prostate cancer incidence in men and breast cancer incidence in women. The relative increase in the world age-standardised incidence rate was 39%. The number of deaths from cancer increased from 130,000 to 146,000. This 13% increase was much lower than anticipated on the basis of demographic changes (37%). The relative decrease in the age-standardised mortality rate was 22%. This decrease was steeper over the 2000-2005 period in both men and women. Alcohol-related cancer incidence and mortality continued to decrease in men. The increasing trend of lung cancer incidence and mortality among women continued; this cancer was the second cause of cancer death among women. Breast cancer incidence increased regularly, whereas mortality has decreased slowly since the end of the 1990s. CONCLUSION: This study confirmed the divergence of cancer incidence and mortality trends in France over the 1980-2005 period. This divergence can be explained by the combined effects of a decrease in the incidence of the most aggressive cancers and an increase in the incidence of less aggressive cancers, partly due to changes in medical practices leading to earlier diagnoses.

A population-based study of the incidence, management and prognosis of hepatic metastases from colorectal cancer.

BACKGROUND: The aim of this population-based study was to evaluate the incidence, management and prognosis of patients with hepatic metastases related to colorectal cancer using data from the Digestive Cancer Registry of Calvados, France. METHODS: Of 1325 patients with colorectal cancer registered between January 1994 and December 1999, 358 developed hepatic metastases. Logistic regression was used to analyse prognostic factors. Survival analysis was carried out with Cox's proportional hazards model. RESULTS: Some 18.8 per cent of patients had synchronous metastases, while 29.3 per cent developed metastases at 3 years. Of patients with hepatic metastases, 17.3 per cent had a surgical resection, 40.2 per cent were treated with palliative chemotherapy and 42.5 per cent had symptomatic treatment. Factors associated with receiving symptomatic treatment only were age over 75 years and more than one metastasis, but not place of treatment. Median survival after a diagnosis of hepatic metastases was 10.7 (range 4.6-23.1) months. Significant adverse prognostic factors were: age over 75 years (P = 0.001), lymph node invasion of primary tumour (P = 0.024), bilateral distribution of metastases (P = 0.001), other metastases (P = 0.004) and symptomatic treatment only (P = 0.041). CONCLUSION: Despite improvement in treatment for hepatic metastases, age and extent of disease remain limiting factors for surgical resection and palliative chemotherapy.

The third component of complement (C3) bound to tumor target cells enhances their sensitivity to killing by activated macrophages.

The third component of complement (C3) bound to P815 tumor cells enhanced their susceptibility to killing by Corynebacterium parvum-activated murine macrophages (M phi). Hemolytically active normal mouse serum and C5-deficient mouse serum were used to deposit complement (C) on P815 tumor cells, in the absence of exogenous antibody, by an alternative pathway mechanism. Cell-bound C3 was detected and was quantified by using a cellular enzyme-linked immunospecific assay. Activated M phi produced tumor cytolysis in a serum-free 16-hr 51Cr-release assay. The lysis of C-treated tumor cells was increased over targets treated with sera containing 10 mM EDTA, heat-inactivated mouse sera, or medium. In addition, C alone did not cause specific 51Cr release. M phi elicited by casein or PBS did not lyse any of the tumor targets tested. The increase in lysis was dependent on the dilution of serum used, and was strongly correlated with the amount of C3 detected on the tumor cells. The enhanced lysis was abrogated by incubating C3-bearing tumor cells with F(ab')2 fragments of a goat anti-mouse C3 antibody. C treatment did not alter the kinetics of tumor cell lysis, nor did it enhance the binding of the targets to effector cells. These results suggest that C may regulate M phi-mediated killing of tumor cells by increasing the lytic efficiency of M phi that are in contact with target-bound C3.

Role of macrophage lipids in regulating tumoricidal activity.

Peritoneal macrophages (M phi) from mice became cytotoxic after incubation with lymphokine (LK); tumoricidal activity was evident with M phi treated with LK for 4 hr, became maximal after 8-12 hr of incubation, and decreased to control levels by 24-36 hr. LK induced marked changes in M phi lipid composition: cellular content of cholesterol (CHOL) and polyunsaturated fatty acid (UFA) content of cellular lipids (especially 18:3) increased two- to threefold after 8 hr when the cells showed maximal tumoricidal activity. Cellular lipid and fatty-acid content returned to control levels by 24 hr when the M phi had lost tumoricidal activity. These changes were not observed with equal numbers of M phi cultured in control supernatants. To analyze the role of CHOL and UFA in M phi tumor cytotoxicity, casein-induced peritoneal M phi were enriched in CHOL or linolenic acid (18:3) and then tested for their ability to kill 1023 tumor cells. The 18:3-enriched cells were markedly tumoricidal, whereas controls cultured in delipidized medium alone or enriched with saturated fatty acid (18:0) were not cytotoxic. CHOL-enriched M phi were not tumoricidal; indeed, these cells were inhibited in their killing after treatment with LK compared to M phi cultured in delipidized medium with LK alone. The effects of 18:3 and CHOL enrichment of the M phi on their metabolic status, inflammatory function, and tumor cell-binding capacity were tested. The 18:3-enriched M phi were depressed in their ability to synthesize protein and in phagocytic activity compared to controls; these cells showed a transient increase in superoxide release. M phi cultured with 18:3 for 48 hr were also cytotoxic for P815 tumor cells, but did not show an enhanced capacity for P815 binding compared to controls. CHOL-enriched M phi were similar to control cells in their protein synthesizing and phagocytic activities; these cells also showed an early transient increase in superoxide release. CHOL-enriched M phi were not cytotoxic for P815 cells, but bound the tumor cells more readily than did the 18:3-enriched M phi. The data suggest that endogenous levels of 18:3 and CHOL can regulate M phi tumor cytotoxicity, but not through regulation of M phi protein synthesis, oxidative metabolism, or augmented capacity for tumor target binding.