Cancer development and its natural history. A cancer prevention perspective

Presenting treatment options in breast cancer consultations: Advice and consent in Italian medical care

Variety, complexity and uncertainty in the therapy outcomes of cancer illness make the treatment recommendation (TR) in oncology a "monumentally difficult task". Previous studies have distinguished unilateral and bilateral formats of treatment recommendations, accordingly to whether, or to what extent, the patient's perspective is included in the consideration of therapeutic options. Others have also shown how the oncologists' presentation of therapeutic options varied accordingly to the severity of the diagnosis and the availability of alternatives. Yet, no study has systemically dentified and compared components of treatment recommendation in oncology on a common set of patients and clinicians. This paper analyzes how different options in breast cancer treatments - radiotherapy, hormone therapy and chemotherapy - are presented and discussed in a set of 12 first post-surgical breast cancer visits carried out by two oncologists of high experience and seniority in two Italian hospitals. Treatment recommendation sequences involving these three option types were analyzed using the methods of conversation analysis. They were also coded for the mention of side effects and treatment burden, and for whether consent to the recommendation was invited, or expressed by the patient. Results show that radiotherapy is presented as presupposed as an extension of surgery and is not further discussed, and hormone therapy is delivered as good news and as not implying any health or lifestyle burdens. Treatment burdens were raised in the much more extensive discussions of chemotherapy, which were also accompanied by a higher chance that the patient was asked for consent to therapy. Implications are drawn as regards the extent to which clinical practice meets theory in communication protocols available in oncology, and how to consider the doctor-patient partnership and the concept of shared decision-making in such an encounter.

Hepatic preneoplasia induction in male Wistar rats: histological studies up to five months post treatment

BACKGROUND

Liver preneoplasia development in rats can be mimicked by an initiation-promotion model that induces the appearance of altered hepatocyte foc (FAH).

AIMS

We compare two initiation-promotion models to evaluate the presence of FAH or additional hepatic pathologies in which other organs were affected up to five month post treatment.

MATERIAL AND METHODS

FAH were induced in male adult Wistar rats with two doses of dietylnitrosamine (DEN, 150 mg/kg bw) followed by 4 doses per week (3 weeks) of 2-acetylaminofluorene (2-AAF, 20 mg/kg bw) or with one dose of DEN (200 mg/kg bw) followed by 2 doses per week (3 weeks) of 2-AAF. DEN 150, DEN 200 and control mice (received the vehicle of the drugs) groups were compared. Rats were euthanized immediately after the last dose of 2-AAF, at 3, 4 and 5 months (n = 3 euthanasia times per group). Samples of livers, lungs, kidneys, pancreatic tissue and small bowel were processed for histological and immunohistochemical analysis.

RESULTS

FAH persisted for 5 months in all livers of the DEN groups. Three months after withdrawal of 2-AAF, one rat from the DEN 150 group developed fibrosis and 5 months after 2-AAF removal another rat from the same group presented a microscopic hyperplastic nodule. Only the lungs had damage compatible with lesions induced by gavage-related reflux in DEN groups.

CONCLUSION

We concluded that up to five month post treatments, FAH persisted in all the livers from the DEN groups; livers from the DEN 200 group showed no other hepatic lesions besides FAH, and only the lungs suffered pathological alterations in both treated groups.

Immunogenic FEAT protein circulates in the bloodstream of cancer patients

BACKGROUND

FEAT is an intracellular protein that potently drives tumorigenesis in vivo. It is only weakly expressed in normal human tissues, including the testis. In contrast, FEAT is aberrantly upregulated in most human cancers. The present study was designed to investigate whether FEAT is applicable to tumor immunotherapy and whether FEAT is discernible in the bloodstream as a molecular biomarker of human cancers.

METHODS

Two mouse FEAT peptides with predicted affinities for major histocompatibility complex H-2Kb and H-2Db were injected subcutaneously into C57BL/6 mice before subcutaneous transplantation of isogenic B16-F10 melanoma cells. Intracellular localization of FEAT was determined by immunogold electron microscopy. Immunoprecipitation was performed to determine whether FEAT was present in blood from cancer patients. A sandwich enzyme-linked immunosorbent assay was used to measure FEAT concentrations in plasma from 30 cancer patients and eight healthy volunteers.

RESULTS

The vaccination experiments demonstrated that FEAT was immunogenic, and that immune responses against FEAT were induced without deleterious side effects in mice. Electron microscopy revealed localization of FEAT in the cytoplasm, mitochondria, and nucleus. Immunoprecipitation identified FEAT in the blood plasma from cancer patients, while FEAT was not detected in plasma exosomes. Plasma FEAT levels were significantly higher in the presence of cancers.

CONCLUSIONS

These findings suggest that FEAT is a candidate for applications in early diagnosis and prevention of some cancers.

Dietary flavonoid intake and Barrett's esophagus in western Washington State

PURPOSE

Flavonoids, concentrated in fruits and vegetables, demonstrate in experimental studies chemopreventive properties in relation to Barrett's esophagus (BE), a precursor lesion for esophageal adenocarcinoma. One case-control investigation reported an inverse association between isoflavone intake and odds of BE, yet no epidemiologic study has considered other flavonoid classes, which are more commonly consumed by Americans.

METHODS

We examined intake of total flavonoids, six flavonoid classes, and lignans among case-control study participants in western Washington State. Food frequency questionnaires were self-completed by BE cases with specialized intestinal metaplasia (n = 170) and matched controls (n = 183).

RESULTS

In logistic regression models adjusted for age, sex, body mass index, and energy intake, the odds ratio (OR) for specialized intestinal metaplasia BE associated with anthocyanidin intake was 0.49 (95% confidence interval: 0.30-0.80, for quartiles 2-4 combined vs. quartile 1), for which wine and fruit juice were major dietary sources. More moderate decreased ORs were noted for flavanones, flavonols, isoflavones, and lignans. A modest increased OR was observed for flavones, for which pizza was the main dietary source in our population.

CONCLUSIONS

Our findings of an inverse association between anthocyanidins and odds of BE suggest that adequate dietary intake of these compounds may lower risk of this cancer precursor lesion.

Assessing estrogen signaling aberrations in breast cancer risk using genetically engineered mouse models

Aberrations in estrogen signaling increase breast cancer risk. Molecular mechanisms that impact breast cancer initiation, promotion, and progression can be investigated using genetically engineered mouse models. Increasing estrogen receptor alpha (ERα) expression levels twofold is sufficient to initiate and promote breast cancer progression. Initiation and promotion can be increased by p53 haploinsufficiency and by coexpressing the nuclear coactivators amplified in breast cancer 1 (AIB1) or the splice variant AIB1Δ3. Progression to invasive cancer is found with coexpression of these nuclear coactivators as well as following a single dose of 7,12-dimethylbenz(a)anthracene. Loss of signal transducer and activator of transcription 5a reduces the prevalence of initiation and promotion but does not protect from invasive cancer development. Cyclin D1 loss completely interrupts mammary epithelial proliferation and survival when ERα is overexpressed. Loss of breast cancer gene 1 increases estrogen signaling and cooperates with ERα overexpression in initiation, promotion, and progression of mammary cancer.

A comparison of the effects of three GM corn varieties on mammalian health

We present for the first time a comparative analysis of blood and organ system data from trials with rats fed three main commercialized genetically modified (GM) maize (NK 603, MON 810, MON 863), which are present in food and feed in the world. NK 603 has been modified to be tolerant to the broad spectrum herbicide Roundup and thus contains residues of this formulation. MON 810 and MON 863 are engineered to synthesize two different Bt toxins used as insecticides. Approximately 60 different biochemical parameters were classified per organ and measured in serum and urine after 5 and 14 weeks of feeding. GM maize-fed rats were compared first to their respective isogenic or parental non-GM equivalent control groups. This was followed by comparison to six reference groups, which had consumed various other non-GM maize varieties. We applied nonparametric methods, including multiple pairwise comparisons with a False Discovery Rate approach. Principal Component Analysis allowed the investigation of scattering of different factors (sex, weeks of feeding, diet, dose and group). Our analysis clearly reveals for the 3 GMOs new side effects linked with GM maize consumption, which were sex- and often dose-dependent. Effects were mostly associated with the kidney and liver, the dietary detoxifying organs, although different between the 3 GMOs. Other effects were also noticed in the heart, adrenal glands, spleen and haematopoietic system. We conclude that these data highlight signs of hepatorenal toxicity, possibly due to the new pesticides specific to each GM corn. In addition, unintended direct or indirect metabolic consequences of the genetic modification cannot be excluded.

Effect of black tea in diethylnitrosamine-induced esophageal carcinogenesis in mice

PURPOSE: To evaluate the effect of black tea on esophageal carcinogenesis induced by the oral administration of diethylnitrosamine (DEN). METHODS: A population of 120 female mice (Mus musculus, strain CF1) were studied for 160 days. The animals were assigned to two control groups and three treatment groups. The control groups received water or tea throughout the study period, while the three experimental groups received DEN weekly, for three consecutive days, and water, tea, or both, in the other days of the week. On completion of the 160-day period, the animals were killed and their esophagi promptly examined macroscopically and subsequently submitted to histopathology (using the hematoxylin-eosin technique). RESULTS: In the comparative analysis between the treatment groups, tumor incidence (macroscopy) was significantly lower in those animals that received black tea besides the carcinogen. As regards the histopathologic changes, there was a greater number of low grade epithelial lesions in the same groups (p < 0.001). CONCLUSION: The animals that received black tea had a lower incidence of effects related to the carcinogen's action, thus indicating that, in this model, the infusion had a significant chemoprophylactic effect on experimental diethylnitrosamine-induced carcinogenesis.

Expression of CDC25 phosphatases in human gastric cancer

BACKGROUND

Gastric cancer may be considered the final step of a progressive imbalance between mucosal cell proliferation and apoptosis. CDC25 phosphatases comprise a multigene family, including CDC25A and CDC25B, that plays a crucial role in the control of cell cycle progression and has been linked to the development of human cancers. The role of CDC25 phosphatases in the pathogenesis of gastric cancers is, however, still largely unknown.

MATERIAL AND METHODS

Immunohistochemical expression of CDC25A and CDC25B was investigated in matched normal and cancerous tissues from 70 patients with gastric cancer (52 intestinal and 18 diffuse type).

RESULTS

In non-cancerous gastric tissues the expression of CDC25A and CDC25B was absent or weak. In gastric cancer tissues, the enhanced immunoreactivity of CDC25 phosphatases was independent of intestinal or diffuse type of gastric cancer. However, the intensity of immunostaining was related to the grade of differentiation of the tumors. Interestingly, c-myc expression was directly correlated with CDC25A and B expression.

CONCLUSIONS

The overexpression of CDC25A and B seems to be a common and very early event in the development of both intestinal and diffuse types of gastric cancer and may play an important role in gastric carcinogenesis.

Adequacy of Colonoscopic Biopsy Specimens for Molecular Analysis: A Comparative Study With Colectomy Tissue

Molecular analyses of tumors are increasingly useful for prognosis and for guiding therapy. Colonoscopic biopsy provides the first source of tissue for most cases of colorectal carcinoma and therefore might become an important source for molecular analyses. We have addressed the question whether molecular analyses of colonoscopic biopsy yield results similar to the findings from the surgical specimen. Further, we analyzed 2 separate areas of the colectomy specimen to assess tumor heterogeneity. We evaluated 3 samples from each of 67 patients for point mutations in the KRAS gene, loss of heterozygosity (LOH) at the Adenomatous Polyposis Coli (APC) and Deleted in Colon Cancer (DCC) genes and for microsatellite instability (MSI) using polymerase chain reaction based techniques. The average time interval between biopsy and surgery was 2.2+/-0.15 weeks. Lesions were from all colon segments and all surgical stages. The degree of agreement between the biopsy and surgical sites was high for APC LOH, MSI, and KRAS mutations (kappa=0.85, 1.00, and 0.93, respectively) but less so for DCC LOH (kappa=0.62). Colonoscopic biopsies are an acceptable source of neoplastic DNA for studies of KRAS, APC LOH, and MSI, but less so for DCC LOH, primarily resulting from technical considerations.

Essiac tea: scavenging of reactive oxygen species and effects on DNA damage

Essiac, a tea reportedly developed by the Ojibwa tribe of Canada and widely publicized as a homeopathic cancer treatment, is prepared from a mixture of four herbs Arctium lappa, Rumex acetosella, Ulmus rubra and Rheum officinale. Each of these herbs has been reported to possess antioxidant and anti-cancer activity. Essiac itself has also been reported to demonstrate anti-cancer activity in vitro, although its effects in vivo are still a matter of debate. We prepared an extract of Essiac tea from a concentration of 25mg/mL and boiled it for 10 min. From this preparation we used concentrations of 5, 10, 25 and 50% to measure Essiac effects. In this study, we examined the effects of Essiac on free radical scavenging and DNA damage in a non-cellular system, as well as the effects Essiac on lipid peroxidation using the RAW 264.7 cell line. We observed, using electron spin resonance, that Essiac effectively scavenged hydroxyl, up to 84% reduction in radical signal at the 50% tea preparation concentration, and superoxide radicals, up to 82% reduction in radical signal also at the 50% tea preparation concentration, as well as prevented hydroxyl radical-induced DNA damage. In addition, Essiac inhibited hydroxyl radical-induced lipid peroxidation by up to 50% at the 50% tea preparation concentration. These data indicate that Essiac tea possesses potent antioxidant and DNA-protective activity, properties that are common to natural anti-cancer agents. This study may help to explain the mechanisms behind the reported anti-cancer effects of Essiac.

CpG island methylation as an early event during adenoma progression in carcinogenesis of sporadic colorectal cancer

BACKGROUND AND AIMS

CpG island methylation is present in various tumors, including colorectal carcinomas, and is thought to be an important mechanism in carcinogenesis. We evaluated the methylation status of primary colorectal tumors to determine its role in the adenoma to carcinoma sequence.

METHODS

The methylation status of APC, THBS1, MGMT, hMLH1 and GSTP1, as determined by methylation specific PCR (MSP), and microsatellite instability (MSI) using three mononucleotide markers were assessed in 40 colorectal adenomas and 36 adenocarcinomas. The correlations of methylation status and MSI with the clinicopathologic parameters of the tumors were determined.

RESULTS

Of the 40 adenomas, 24 (60%) were methylated at one or more loci, and 12 (30%) at two or more loci (CpG island methylation phenotype-high, CIMP-H). Of 36 carcinomas, 27 (75%) were methylated at one or more loci and 11 (30.5%) at two or more loci (CIMP-H). THBSI was the most frequently methylated locus in both adenomas (n = 19, 47.5%) and carcinomas (n = 16, 44.4%). Overall, methylation status of adenomas and carcinomas did not differ significantly (P = 0.53), nor did the methylation status of individual genes. For adenomas, size (P = 0.049) and histologic classification of the villous components (P = 0.018) were each associated with methylation status. For carcinomas, however, no clinicopathologic variable was related to methylation status. MSI was detected in three adenomas (7.5%) and five carcinomas (13.9%), and was closely correlated with hMLH1 methylation (P < 0.001).

CONCLUSIONS

In colorectal tumors, CpG island methylation of tumor suppressor genes appears to be common and may be involved in the progression of adenomas.

Resveratrol scavenges reactive oxygen species and effects radical-induced cellular responses

Scavenging or quenching of the reactive oxygen species (ROS) involved in oxidative stress has been the subject of many recent studies. Resveratrol, found in various natural food products, has been linked to decreased coronary artery disease and preventing cancer development. The present study measured the effect of resveratrol on several different systems involving the hydroxyl, superoxide, metal/enzymatic-induced, and cellular generated radicals. The rate constant for reaction of resveratrol with the hydroxyl radical was determined, and resveratrol was found to be an effective scavenger of hydroxyl, superoxide, and metal-induced radicals as well as showing antioxidant abilities in cells producing ROS. Resveratrol exhibits a protective effect against lipid peroxidation in cell membranes and DNA damage caused by ROS. Resveratrol was also found to have a significant inhibitory effect on the NF-kappaB signaling pathway after cellular exposure to metal-induced radicals. It was concluded that resveratrol in foods plays an important antioxidant role.

Cancer chemopreventive activities of S-3-1, a synthetic derivative of danshinone

Salvia miltiorrhiza is a traditional Chinese medicine which has been well documented for its anti-cancer effects. Based on the structure of danshinone, one of the active compounds derived from Salvia miltiorrhiza, we synthesized a simplified phenolic analog, S-3-1, and tried to explore its possible actions in preventing the development of cancer. With the Ames test, S-3-1 was found to efficiently suppress the mutagenicity of benzo[alpha]pyrene. This result is consistent with the inhibitory effect of S-3-1 on the activation of benzo[alpha]pyrene by hepatic microsomal enzymes. Besides the anti-initiation effects, S-3-1 could significantly inhibit the croton oil-induced increase of mouse skin epithermal ornithine decarboxylase activity. Moreover, S-3-1 quenched both superoxide and hydroxyl free radicals whereas it inhibited lipid peroxidation in the in vitro model. These results suggest that S-3-1 might act as anti-initiation and anti-promotion agents through reversing the biochemical alterations induced by carcinogen during carcinogenesis. Therefore, we further investigated the effects of S-3-1 on carcinogenesis. In vitro, S-3-1 inhibited the benzo[alpha]pyrene-induced transformation of V79 Chinese hamster lung fibroblasts. At 10-40 mg/kg, S-3-1 was found to inhibit the development of DMBA/croton oil-induced skin papilloma in mice through decreasing the incidence of papilloma, prolonging the latent period of tumor occurrence and reducing tumor number per mouse in a dose-dependent manner. We concluded from this study that S-3-1 might be developed as a new chemopreventive drug.

Genetic pathways in colorectal and other cancers

Cells from cancers show aberrant behaviour such as unrestrained growth, invasion into adjacent tissue and metastasis. All these features of cancer cell behaviour can be explained in terms of genetic changes and the functional impact of these changes. In this review, colorectal cancer (CRC) is examined as a classical example of multistep carcinogenesis. First there is an overview which shows that cancers develop by a process of somatic evolution. This gives rise to preferred genetic pathways of tumorigenesis. The factors which may influence the development and ultimate choice of genetic pathways are then examined. Next, CRC is studied as a specific disease and the putative genetic pathways are described. The mutations that comprise these pathways and the possible functional sequelae of these are explored. The review concludes with a look at those avenues which may further elucidate the natural history of CRC and lead to improved therapy.

Genetic pathways in colorectal and other cancers

Cells from cancers show aberrant behaviour such as unrestrained growth, invasion into adjacent tissue and metastasis. All these features of cancer cell behaviour can be explained in terms of genetic changes and the functional impact of these changes. In this review, colorectal cancer (CRC) is examined as a classical example of multistep carcinogenesis. First there is an overview which shows that cancers develop by a process of somatic evolution. This gives rise to preferred genetic pathways of tumorigenesis. The factors which may influence the development and ultimate choice of genetic pathways are then examined. Next, CRC is studied as a specific disease and the putative genetic pathways are described. The mutations that comprise these pathways and the possible functional sequelae of these are explored. The review concludes with a look at those avenues which may further elucidate the natural history of CRC and lead to improved therapy.

Changes in Bcl-2 and p53 expression in recurrent B-cell lymphomas

The aim of this study was to investigate the changes involved in the evolution of nine cases of recurrent B-cell lymphomas. Using the polymerase chain reaction (PCR) on formalin-fixed, paraffin-embedded tissue from both the primary and the recurrent lymphoma of each case, monoclonality was demonstrated in every tumour. In all nine cases, the recurrent lymphoma was shown to belong to the same clone as the primary lymphoma. Eight of these cases were then investigated by immunohistochemistry for changes in Bcl-2 and p53 expression. Five out of eight of the primary lymphomas showed Bcl-2 overexpression. Two of the three cases initially negative for Bcl-2 expression became positive in the recurrence. One out of eight of the primary lymphomas was positive for p53 expression. Of the seven negative cases, one became positive for p53 expression in the recurrence. Both of the p53-positive cases showed high-grade histology. This study shows that Bcl-2 overexpression is probably an important early event in the development of B-cell lymphomas, although it may occur as a post-neoplastic event. p53 mutation is probably more important as a late event and may be associated with high-grade transformation.

Risk assessment of d-limonene: an example of male rat-specific renal tumorigens

The naturally occurring food constituent d-limonene has been found to cause tumors at high doses only in the kidney of the male rat in association with the development of hyaline droplet nephropathy. In contrast, neither kidney tumors nor the associated nephropathy have been found in female rats or mice at much higher doses. Adult male rats produce large quantities of a specific low-molecular-weight protein in the liver, which is known as alpha 2U-globulin (alpha 2U-g). With administration of sufficient doses of d-limonene to male rats, this protein has been found to accumulate excessively in the P2 segment cells of renal proximal tubules, resulting in hyaline droplet formation as a manifestation of protein overload. Hyaline droplet accumulation is the first stage in a unique sequence of nephropathic lesions (also known as alpha 2U-g nephropathy), including granular casts in the outer medulla and linear mineralization in the papilla. The mechanism underlying protein accumulation appears to be the reversible binding of chemical to alpha 2U-g with subsequent prolongation of its half-life in the tubule cell. In the case of d-limonene, the minor metabolite d-limonene-1,2-oxide has been shown to be the primary chemical species that binds reversibly to alpha 2U-g, impeding the normal process of lysosomal proteinase degradation of alpha 2U-g. The ensuing nephropathy is associated with a sustained increase in compensatory renal tubule cell proliferation, which provides the putative mechanistic link with renal tumor formation possibly through tumor promotion of spontaneously initiated cells or enhanced spontaneous mutagenesis. This proposed mechanism has been supported by additional information, including negative genotoxicity tests for d-limonene and its oxide metabolites, experimentally verified tumor promotion, and enhanced cell proliferation primarily in P2 segment tubule cells in male F344 rats, but no such effects in the alpha 2U-g-deficient NBR rat. The mechanism of d-limonene tumor development does not appear to be possible in humans since neither the quantity nor the type of protein that binds d-limonene or d-limonene-1,2-oxide is present. The deduction that the renal tumors induced in male rats are not relevant to human carcinogenicity in the hazard evaluation step of risk assessment completes the evaluation of human risk for d-limonene. Consequently, it can be concluded that d-limonene does not pose any carcinogenic or nephrotoxic risk to humans.(ABSTRACT TRUNCATED AT 400 WORDS)