The relationship between smoking exposure and p53 overexpression in colorectal cancer

Docetaxel and cisplatin induction chemotherapy with or without fluorouracil in locoregionally advanced head and neck squamous cell carcinoma: A real-world data study

OBJECTIVE

To evaluate outcomes of locoregionally advanced patients with Head and Neck Squamous Cell Carcinoma (HNSCC) treated with Induction Therapy (ICT).

METHODS

Toxicity, response rate, and Event-Free Survival (EFS) and Overall Survival (OS) were evaluated in patients treated with docetaxel, cisplatin, and 5-Fluorouracil (TPF) or docetaxel and Cisplatin (TP).

RESULTS

ICT regimens did not alter response to ICT, and patients' EFS and OS. Cox multivariate analysis identified stable or progressive disease (HR = 5.56) and interval between cycles ≥28 days (HR = 2.79) as predictors of lower EFS, and ECOG ≥ 1 (HR = 3.42), stable or progressive disease (HR = 4.67), and interval between cycles ≥28 days (HR = 2.73) as predictors of lower OS.

CONCLUSION

Our findings indicate TP as a good treatment option for locoregionally advanced HNSCC, especially in socioeconomically limited settings.

LEVEL OF EVIDENCE: 3

Association of cigarette smoking with risk of colorectal cancer subtypes classified by gut microbiota

INTRODUCTION

Both cigarette smoking and gut microbiota play important roles in colorectal carcinogenesis. We explored whether the association between smoking and colorectal cancer (CRC) risk varies by gut microbial enterotypes and how smoking-related enterotypes promote colorectal carcinogenesis.

METHODS

A case-control study was conducted. Fecal microbiota was determined by 16S rDNA sequencing. The cases with CRC or adenoma were subclassified by gut microbiota enterotypes. Multivariate analyses were used to test associations between smoking and the odds of colorectal neoplasm subtypes. Mann-Whitney U tests were used to find differential genera, genes, and pathways between the subtypes.

RESULTS

Included in the study were 130 CRC patients (type I: n=77; type II: n=53), 120 adenoma patients (type I: n=66; type II: n=54), and 130 healthy participants. Smoking increased the odds for type II tumors significantly (all p for trend <0.05) but not for type I tumors. The associations of smoking with increased odds of colorectal neoplasm significantly differed by gut microbiota enterotypes (p<0.05 for heterogeneity). An increase in carcinogenic bacteria (genus Escherichia shigella) and a decrease in probiotics (family Lachnospiraceae and Ruminococcaceae) in type II tumors may drive disease progression by upregulating oncogenic signaling pathways and inflammatory/oxidative stress response pathways, as well as protein phospholipase D1/2, cytochrome C, and prostaglandin-endoperoxide synthase 2 expression.

CONCLUSIONS

Smoking was associated with a higher odds of type II colorectal neoplasms but not type I tumors, supporting a potential role for the gut microbiota in mediating the association between smoking and colorectal neoplasms.

Association between smoking and colorectal cancer in Eastern Mediterranean Regional Office (EMRO): A systematic review and meta-analysis

Background

Smoking poses a significant risk for colorectal cancer (CRC), considered the third leading reason for cancer-related deaths worldwide. However, there has been limited research on the relationship between smoking and CRC in the Eastern Mediterranean Regional Office (EMRO). Therefore, a meta-analysis was conducted to combine available data and gain a comprehensive understanding of the relationship between smoking and CRC in EMRO.

Methods

Two independent researchers searched PubMed, Scopus, and Web of Science until December 2022. The included studies were checked for risk of bias administering the Newcastle-Ottawa scale. Heterogeneity was evaluated using I2 statistics and the Cochrane test. Publication bias was determined through funnel plot analysis and Egger's regression test. Additionally, a meta-regression analysis explored the impact of a country's Human Development Index (HDI) on the relationship between smoking and CRC.

Results

The final analysis included 26 studies, revealing a significant association between smoking and CRC (OR = 1.40; 95% CI: 1.11 - 1.78; P = 0.004). Moreover, smoking had a more pronounced adverse effect on CRC in countries with higher HDIs compared to those with lower HDIs (OR = 1.30; 95% CI: 0.99 - 1.71; P = 0.054).

Conclusions

Our findings underscore the importance of implementing smoking cessation programs and policies in EMRO countries, as they demonstrate a positive relationship between smoking and the risk of CRC. Furthermore, the results suggest that a country's level of human development may influence the association between smoking and CRC. Further research is needed to investigate this potential connection and develop targeted public health interventions.

Polymorphisms in methylenetetrahydrofolate reductase gene (MTHFR) and the age of onset of sporadic colorectal adenocarcinoma

BACKGROUND AND AIMS

Evidence is accumulating for a role of folate in the aetiology of colorectal cancer (CRC). The methylenetetrahydrofolate reductase (MTHFR) gene, involved in folate metabolism, is polymorphic in humans. Since it is unknown whether the MTHFR C677T and A1298C polymorphisms alter the risk for CRC, this was the aim of our study.

MATERIALS AND METHODS

Genomic DNA from 102 sporadic colorectal adenocarcinoma (SCA) patients and 300 controls was analyzed by polymerase chain reaction followed by restriction digestion for the polymorphisms analyses.

RESULTS/FINDINGS

The frequencies of MTHFR C677T and A1298C genotypes were similar in patients and controls. Similar overall risks for disease were seen in individuals with the distinct MTHFR genotypes. However, an excess of the MTHFR 677TT and 677CT genotypes was seen in patients under 50 years, compared with patients at an older age (19.2 vs 13.1% and 61.6 vs 39.5%, respectively; P = 0.04). The differences were more prominent when the frequency of the 677TT plus 677CT genotype was seen in both group of patients (80.8 vs 52.6%, respectively; P = 0.01), and in younger patients compared to controls (80.8 vs 52.3%, P < 0.01). Individuals with the combined genotype had 3.82-fold (95% confidence interval, 1.41-10.42) increased risk of developing SCA under 50 years, compared with those harboring the wild-type genotype.

INTERPRETATION/CONCLUSION

These results suggest a role for the MTHFR 677TT plus 677CT genotype in increasing SCA diagnosed at a low age in southeastern Brazil, but additional studies with larger sample sizes should be carried out to clarify this issue.

GSTM1 and GSTT1 Polymorphisms, Cigarette Smoking, and Risk of Colon Cancer: A Population-based Case-control Study in North Carolina (United States)

Cigarette smoke is a risk factor for colon cancer, but the importance of dose and interaction with genetic susceptibility remain poorly understood. We used data from a population-based case control study, to examine the association between cigarette smoking and colon cancer in African Americans and whites, and colon cancer and polymorphisms in GSTM1 and GSTT1. A total of 554 cases of primary colon cancer and 874 controls were included in this analysis. We found no association between cigarette smoking (ever versus never) and colon cancer in African Americans (odds ratio (OR)=0.93, 95% confidence interval (CI)=0.65-1.33). In contrast, there was an increased risk of cigarette smoking in whites (OR=1.43, CI=1.05-1.94). There was a small increased risk of colon cancer for individuals with GSTM1 null (African Americans, OR=1.43, CI, 0.98-2.09; whites, OR=1.19, CI, 0.90-1.58) and a decreased risk of colon cancer for individuals with GSTT1 null (African Americans, OR=0.59, CI: 0.40-0.86; whites, OR=0.72, CI: 0.53-1.00). There were weak interactions between GSTT1 null and cigarette smoking in whites, and GSTM1 null genotype and cigarette smoking in African Americans. GSTT1 and GSTM1 polymorphisms may be weakly related to colon cancer risk and there may be racial differences in gene-smoking interactions.

Tobacco, alcohol, and p53 overexpression in early colorectal neoplasia

Background

The p53 tumor suppressor gene is commonly mutated in colorectal cancer. While the effect of p53 mutations on colorectal cancer prognosis has been heavily studied, less is known about how epidemiologic risk factors relate to p53 status, particularly in early colorectal neoplasia prior to clinically invasive colorectal cancer (including adenomas, carcinoma in situ (CIS), and intramucosal carcinoma).

Methods

We examined p53 status, as measured by protein overexpression, in 157 cases with early colorectal neoplasia selected from three New York City colonoscopy clinics. After collecting paraffin-embedded tissue blocks, immunohistochemistry was performed using an anti-p53 monoclonal mouse IgG₂a [BP53-12-1] antibody. We analyzed whether p53 status was different for risk factors for colorectal neoplasia relative to a polyp-free control group (n = 508).

Results

p53 overexpression was found in 10.3%, 21.7%, and 34.9%, of adenomatous polyps, CIS, and intramucosal cases, respectively. Over 90% of the tumors with p53 overexpression were located in the distal colon and rectum. Heavy cigarette smoking (30+ years) was associated with cases not overexpressing p53 (OR = 1.8, 95% CI = 1.1–2.9) but not with those cases overexpressing p53 (OR = 1.0, 95% CI = 0.4–2.6). Heavy beer consumption (8+ bottles per week) was associated with cases overexpressing p53 (OR = 4.0, 95% CI = 1.3–12.0) but not with cases without p53 overexpression (OR = 1.6, 95% CI = 0.7–3.7).

Conclusion

Our findings that p53 overexpression in early colorectal neoplasia may be positively associated with alcohol intake and inversely associated with cigarette smoking are consistent with those of several studies of p53 expression and invasive cancer, and suggest that there may be relationships of smoking and alcohol with p53 early in the adenoma to carcinoma sequence.

Modifiable risk factors for colon cancer

Although many mechanisms remain unclear, a large body of evidence indicates that several dietary and lifestyle factors are likely to have a major influence on the risk of colon cancer. Physical inactivity, excess body weight, and a central deposition of adiposity are consistent risk factors. Overconsumption of energy is likely to be one of the major contributors to the high rates of colon cancer in Western countries. Beyond their influence on energy balance, the independent role of specific macronutrients remain controversial. Red meat, processed meats, and perhaps refined carbohydrates contribute to risk. Recent evidence indicate that chronic hyperinsulinemia may increase risk of colon cancer. As insulin resistance and subsequent hyperinsulinemia is induced by excess energy intake and some aspects of the Western diet (e.g., saturated fats and refined carbohydrates), insulin may be a focus of factors influencing colon cancer risk. Recent evidence also points to a role of IGF-1, but our understanding of modifiable factors that influence levels of these is poor at present. Of note is that hyperinsulinemia increases free IGF-1 exposure [25]. High alcohol consumption, probably in combination with a diet low in some micronutrients such as folate and methionine, and smoking early in life are likely to increase risk of colon cancer. Recent epidemiologic studies have tended not to support a strong influence of fiber; instead, some micronutrients or phytochemicals in fiber-rich foods may be important. Folate is one such nutrient that has received attention lately and is being studied in randomized intervention trials. Agents with chemopreventive properties, such as aspirin and postmenopausal estrogens, have potential adverse effects so a careful consideration of the risk-benefit ratio is required before general recommendations can be made. Other NSAIDs with a potential for reduced toxicity, such as celecoxib, are currently being evaluated for efficacy and toxicity. The overwhelming evidence indicates that primary prevention of colon cancer is feasible. At least 70% of colon cancers may be preventable by moderate changes in diet and lifestyle [197]. Secondary prevention, through screening by sigmoidoscopy and colonoscopy, is also critically important to prevent mortality from colon cancer; however, many of the diet and lifestyle risk factors for colon cancers are the same for cardiovascular disease and for some other cancers, so focusing on the modifiable risk factors for colon cancer is likely to have many additional benefits beyond this cancer.

Intakes of selected nutrients and food groups and risk of ovarian cancer

In a hospital-based case-control study, we examined dietary intakes of selected nutrients and food groups and ovarian cancer risk among 496 women with primary, histologically confirmed epithelial ovarian cancer and 1,425 women with nonneoplastic diagnoses, ages 20-87 years, admitted to Roswell Park Cancer Institute between 1982 and 1998. Data on diet and other relevant risk factors in the few years before admission were collected with a self-administered questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression adjusting for age, education, region of residence, regularity of menstruation, family history of ovarian cancer, parity, age at menarche, oral contraceptive use, and energy intake. Women in the highest vs. the lowest quartile of total energy had a weak increase in risk (OR = 1.25, 95% CI = 0.90-1.73). Significantly reduced risks were associated with higher intakes of dietary fiber (OR = 0.57, 95% CI = 0.38-0.87), vitamin A (OR = 0.66, 95% CI = 0.45-0.98), carotenoid (OR = 0.64, 95% CI = 0.43-0.93), vitamin E (OR = 0.58, 95% CI = 0.38-0.88), beta-carotene (OR = 0.68, 95% CI = 0.46-0.98), and total fruit and vegetable intake (OR = 0.62, 95% CI = 0.42-0.92). Our findings suggest that a diet high in plant foods may be important in reducing risk of ovarian cancer.

Cigarette smoking and rheumatoid arthritis

OBJECTIVES

To examine and explore the potential relationships among the following: the incidence/severity of rheumatoid arthritis (RA), the extra-articular manifestations of RA, vascular disease, certain specific malignancies, the p53 tumor suppressor gene, and cigarette smoking.

METHODS

The medical literature was reviewed from 1985 to 2001 with the assistance of a MEDLINE search using the key words vascular disease, smoking, protein p53, RA, rheumatoid vasculitis, cancer, and malignancies. A qualitative review was performed after all articles were abstracted and new information summarized.

RESULTS

Cigarette smoking has been increasingly shown in epidemiologic and case-control studies to be an important risk factor for both the incidence and severity of RA, especially in seropositive men. Further, there is evidence of a downward trend in incidence of extra-articular manifestations of RA, especially RA vasculitis, observed with a decrease in worldwide tobacco use and overall improved mortality in RA. The association of cigarette smoking with lung and other cancers and its link to vascular disease (including Buerger's disease) and atherosclerosis appears secure. Mutations or alterations in p53, a suppressor gene that regulates cell growth, have been found in certain cancers, cigarette smokers, and in patients with RA.

CONCLUSIONS

Cigarette smoking appears to have an undeniable link to the pathogenesis of vascular disease of many types, including the possibility of a strong causal connection to rheumatoid vasculitis. The observations worldwide of decreasing tobacco use along with secular trends of diminished RA vasculitis and extra-articular manifestations, and with improved survival, points to a better outcome for our patients. The example of p53 may be a first step in the discovery of additional links between environmental triggers and phenotypic expression of chronic illness.

p53 over-expression and p53 mutations in colon carcinomas: relation to dietary risk factors

Epidemiological studies have suggested that dietary factors may differently affect p53-dependent and p53-independent pathways to colon cancer. Results of such studies may depend on the method used to assess p53 status. This case-control study of 185 colon-cancer cases and 259 controls examines this relation, using both immunohistochemistry and SSCP(exons 5-8)/sequencing to detect p53 abnormalities. Of 185 carcinomas analyzed using immunohistochemistry, 81 (44%) were categorized as p53 over-expression. p53 mutations were detected in 59 tumors (32%). A slight increase in risk observed for intake of saturated fat was largely due to an increased risk in cases without p53 over-expression (OR per 16.1 g/day, 1.46; 95% CI, 1.08-1.97), and no association in cases with p53 over-expression (OR, 1.07, 95% CI, 0.78-1.47). However, findings were less pronounced when cases were classified by mutation analysis (wild-type OR, 1.33; 95% CI, 1.01-1.75; mutated OR, 1.16; 95% CI, 0.81-1.65). Similar results were observed for total fat intake. For other nutrients and for vegetable and meat food groups no differences in risk for either p53 pathway were observed, independent of the laboratory technique used. Interestingly, in cases with transversion mutations in the p53 gene, an increased risk was observed for saturated fat (OR, 2.00; 95% CI, 0.97-4.14), in contrast to those with mutations at CpG sites (OR, 0.93; 95% CI, 0.55-1.57). An increase in colon-cancer risk for the p53-independent pathway due to fat intake, is more pronounced when using immunohistochemistry. However, mutation analysis is needed to study the possible association with a small group of tumors with transversion mutations.

Aspirin use and p53 expression in colorectal cancer

p53 protein overexpression indicates loss of tumor suppressor activity and is the most common genetic alteration in colorectal neoplasms. Epidemiologic and experimental studies suggest that regular use of aspirin may reduce colorectal cancer risk. We set out to determine whether p53 overexpression of the colorectum was associated with a patient's history of aspirin use. Self-administered questionnaires, including information on aspirin use, were obtained from 163 patients with nonfamilial colorectal cancer and from 326 healthy controls. Nuclear p53 protein overexpression using anti-p53 CM-1 polyclonal antibody was observed in 44.8% (73/163) of patients' tumors. A nonsignificant inverse association was observed between use of aspirin and colorectal cancer. Compared with that for nonusers, the odds ratio (OR) for individuals who took aspirin at least twice weekly was 0.68 (95% confidence interval [95% CI]: 0.39-1.18). The odds ratio for those individuals who used aspirin for less than 5 years was 0.54 (95% CI: 0.24-1.23), and 0.80 (95% CI: 0.42-1.51) for those who used aspirin for 5 years or more, when compared with nonusers. An inverse association of regular aspirin use (two times per week or more) was found both for cases with p53 overexpression (OR: 0.79; 95% CI: 0.39-1.59), and for cases without p53 overexpression (OR: 0.56; 95% CI: 0.25-1.22). There was little evidence of a difference in the effect of aspirin use on cancer risk between cases with and without p53 overexpression, even after adjustment for potential confounders.

Overexpression of p53 protein correlates with a high risk of malignant transformation of adenomas in patients with multiple colorectal adenomas

To assess the correlation of p53 oncoprotein expression with the high risk of developing carcinomas in patients with multiple colorectal adenomas, 25 cases with histologic carcinoma in adenoma (CIA) were examined by immunohistochemistry using a monoclonal antibody specific to human p53 protein (wild and mutant). The 25 cases were classified into multiple and single groups. The former contained 13 cases with synchronous multiple colorectal adenomas (one to six adenomas) and adenocarcinoma. The latter included 12 cases with single CIA only. This study revealed an overall incidence of 57.14% of p53 overexpression in carcinomatous lesions and 31.9% in adenomatous lesions, which was statistically significant (P < 0.05). The carcinomatous lesions showed a diffuse staining pattern, whereas the adenomatous lesions showed a focal pattern. A significant finding was that the incidence of p53 overexpression was significantly higher in multiple groups (81.25%) than in single groups (31.43%) in the carcinomatous (P < 0.01) rather than in the adenomatous (P < 0.05) lesions. There were no correlations between p53 overexpression and proliferation activity or carcinoembryonic antigen expression. The results indicate that p53 abnormality may be an important genetic factor responsible for the high risk of developing carcinomas in patients with multiple adenomas.