Schizophrenia and cancer: is angiogenesis a missed link?

The Risk and The Course of Cancer Among People with Severe Mental Illness

The paucity of data regarding patients with Serious Mental Illness (SMI) and cancer is alarming given the fact that people with SMI, especially schizophrenia, bipolar disorders and severe depressive disorders, have in general poorer access to physical health care and higher morbidity and mortality because of physical illnesses. The aims of this review were to examine the current evidence from existing literature on the risk of developing cancer and its course among people with SMI. Equivocal results emerge regarding the risk of developing some kind of cancer among people with SMI, with contrasting data on a possible higher, similar or lower risk in comparison with the general population. In contrast, a series of studies have pointed out that patients with SMI who develop cancer are less likely to receive standard levels of cancer care, both in terms of screening, diagnosis and treatment. Also, the mortality for cancer has been confirmed to be higher than the general population. A global sensitization about these problems is mandatory in an era in which community psychiatry has been developed in all countries and that policies of prevention, treatment, follow up, and palliative care should regard all the segments of the population, including people with SMI, through an interdisciplinary approach.

Neurodevelopmental disorders and cancer networks share pathways, but differ in mechanisms, signaling strength, and outcome

Epidemiological studies suggest that individuals with neurodevelopmental disorders (NDDs) are more prone to develop certain types of cancer. Notably, however, the case statistics can be impacted by late discovery of cancer in individuals afflicted with NDDs, such as intellectual disorders, autism, and schizophrenia, which may bias the numbers. As to NDD-associated mutations, in most cases, they are germline while cancer mutations are sporadic, emerging during life. However, somatic mosaicism can spur NDDs, and cancer-related mutations can be germline. NDDs and cancer share proteins, pathways, and mutations. Here we ask (i) exactly which features they share, and (ii) how, despite their commonalities, they differ in clinical outcomes. To tackle these questions, we employed a statistical framework followed by network analysis. Our thorough exploration of the mutations, reconstructed disease-specific networks, pathways, and transcriptome levels and profiles of autism spectrum disorder (ASD) and cancers, point to signaling strength as the key factor: strong signaling promotes cell proliferation in cancer, and weaker (moderate) signaling impacts differentiation in ASD. Thus, we suggest that signaling strength, not activating mutations, can decide clinical outcome.

The presence of polymorphisms in genes controlling neurotransmitter metabolism and disease prognosis in patients with prostate cancer: a possible link with schizophrenia

Polymorphisms of neurotransmitter metabolism genes were studied in patients with prostate cancer (PC) characterized by either reduced or extended serum prostate-specific antigen doubling time (PSADT) corresponding to unfavorable and favorable disease prognosis respectively. The ‘unfavorable prognosis’ group (40 cases) was defined by PSADT ≤ 2 months, whereas patients in the ‘favorable prognosis’ group (67 cases) had PSADT ≥ 30 months. The following gene polymorphisms known to be associated with neuropsychiatric disorders were investigated: a) the STin2 VNTR in the serotonin transporter SLC6A4 gene; b) the 30-bp VNTR in the monoamine oxidase A MAOA gene; c) the Val158Met polymorphism in the catechol-ortho-methyltransferase COMT gene; d) the promoter region C-521T polymorphism and the 48 VNTR in the third exon of the dopamine receptor DRD4 gene.

The STin2 12R/10R variant of the SLC6A4 gene (OR = 2.278; 95% CI = 0.953–5.444) and the -521T/T homozygosity of the DRD4 gene (OR = 1.579; 95% CI = 0.663–3.761) tended to be overrepresented in PC patients with unfavorable disease prognosis. These gene variants are regarded as protective against schizophrenia, and the observed trend may be directly related to a reduced PC risk described for schizophrenia patients. These results warrant further investigation of the potential role of neurotransmitter metabolism gene polymorphisms in PC pathogenesis.

Genetic Profiles Playing Opposite Roles of Pathogenesis in Schizophrenia and Glioma

Background

Patients diagnosed with schizophrenia were found having lower risks to develop cancers, including glioma. Based on this epidemiology, we hypothesized that there were gene profiles playing opposite roles in pathogenesis of schizophrenia and glioma.

Methods

Based on GEO datasets and TCGA, key genes of schizophrenia genes on the opposite development of glioma were screened by different expressed genes (DEGs) screening, weighted gene coexpression network analysis (WGCNA), disease-specific survival (DSS), and glioma grading and verified by gene set enrichment analysis (GSEA).

Results

First, 612 DEGs were screened from schizophrenia and control brain samples. Second, 134 key genes more specific to schizophrenia were left by WGCNA, with 93 key genes having annotations in TCGA. Third, DSS of glioma helped to find 42 key gene expressions of schizophrenia oppositely associated with survival of glioma. Finally, 24 key genes showed opposite expression trends in schizophrenia and different glioma grading, i.e., the upregulated key genes in schizophrenia expressed increasingly in higher grade glioma, and vice versa. CAMK2D and MPC2 were taken as the examples and evaluated by GSEA, which indeed showed opposite trends in the same pathways of schizophrenia and glioma.

Conclusion

This workflow of selecting novel targeted genes which may have opposite roles in pathogenesis of two diseases was firstly and innovatively generated by our team. Some filtered key genes were indeed found by their potential effects in several mechanism studies, indicating our process could be effective to generate novel targeted genes. These 24 key genes may provide potential directions for future biochemical and pharmacotherapeutic research studies.

Low Dose of Penfluridol Inhibits VEGF-Induced Angiogenesis

Metastasis is considered a major burden in cancer, being responsible for more than 90% of cancer-related deaths. Tumor angiogenesis is one of the main processes that lead to tumor metastasis. Penfluridol is a classic and commonly used antipsychotic drug, which has a great ability to cross the blood–brain barrier. Recent studies have revealed that penfluridol has significant anti-cancer activity in diverse tumors, such as metastatic breast cancer and glioblastoma. Here, we aim to identify the effect of low doses of penfluridol on tumor microenvironment and compare it with its effect on tumor cells. Although low concentration of penfluridol was not toxic for endothelial cells, it blocked angiogenesis in vitro and in vivo. In vitro, penfluridol inhibited VEGF-induced primary endothelial cell migration and tube formation, and in vivo, it blocked VEGF- and FGF-induced angiogenesis in the matrigel plug assay. VEGF-induced VEGFR2 phosphorylation and the downstream p38 and ERK signaling pathways were not affected in endothelial cells, although VEGF-induced Src and Akt activation were abrogated by penfluridol treatment. When cancer cells were treated with the same low concentration of penfluridol, basal Src activation levels were mildly impaired, thus impacting their cell migration and wound healing efficiency. The potential of cancer-induced paracrine effect on endothelial cells was explored, although that did not seem to be a player for angiogenesis. Overall, our data demonstrates that low penfluridol levels, similar to the ones clinically used for anti-psychotic conditions, suppress angiogenic efficiency in the tumor microenvironment.

Association of Schizophrenia With the Risk of Breast Cancer Incidence: A Meta-analysis

Importance

Patients with schizophrenia are considered to have many risk factors for the development of cancer. However, the incidence of breast cancer in women with schizophrenia compared with the general population remains uncertain.

Objective

To perform an updated meta-analysis to evaluate the association between schizophrenia and the risk of breast cancer.

Data Sources

A systematic search of the PubMed and EMBASE databases was conducted using the search terms schizophrenia, schizophrenic, psychosis, combined with breast and cancer, tumor, neoplasm, or carcinoma. The final literature search was performed on August 15, 2017.

Study Selection

Cohort studies reporting the standardized incidence ratio (SIR) for the risk of breast cancer in women with schizophrenia compared with the general population.

Data Extraction and Synthesis

The meta-analysis adhered to Meta-analysis of Observational Studies in Epidemiology and the Cochrane Handbook for Systematic Reviews of Interventions. Data extraction was performed independently. A random-effects model was used to pool the results, and a recently proposed prediction interval was calculated to describe the heterogeneity.

Main Outcomes and Measures

The SIR for the risk of breast cancer in women with schizophrenia compared with the general population or those without schizophrenia.

Results

Twelve cohorts including 125 760 women were included in this meta-analysis. The results of the meta-analysis showed that schizophrenia was associated with a significantly increased risk of breast cancer incidence in women (SIR, 1.31; 95% CI, 1.14-1.50; P < .001), with significant heterogeneity (P < .001; I2 = 89%). Substantial between-study variance was also suggested by the wide prediction interval (0.81-2.10), which indicated that it is possible that a future study will show a decreased breast cancer risk in women with schizophrenia compared with the general population. The subgroup analysis results showed that the association was not significantly affected by whether breast cancer cases were excluded at baseline or the sample size of the included studies.

Conclusions and Relevance

The incidence of breast cancer in women with schizophrenia is higher than that of the general female population. However, significant heterogeneity exists among the included studies. Women with schizophrenia deserve intensive prevention and treatment of breast cancer.

Cancer in patients with schizophrenia: What is the next step?

People with schizophrenia, who constitute approximately 0.3-1% of the general population, have a nearly 20% shorter life expectancy than the general population. The incidence of varied types of cancers in patients with schizophrenia is controversial. The majority of previous research has demonstrated that patients who have schizophrenia and cancer have early mortality compared to the general population with cancer. The causes of early mortality in patients with schizophrenia and cancer might be attributed to a lower cancer screening rate and lack of effective treatment, including: (i) patient factors, such as poor lifestyle, passive attitude toward treatment, or comorbidity; (ii) physician factors, such as physician bias, which may decrease the delivery of care for individuals with mental disorders; and (iii) hospital administration factors, such as stigma and discrimination. Additional studies on patients with schizophrenia and cancer are warranted and should include the following: a comprehensive review of previous studies; a focus on differentiating the specific types of cancer; and methods for improvement. To decrease the early mortality of patients with schizophrenia, the following measures are proposed: (i) enhance early detection and early treatment, such as increasing the cancer screening rate for patients with schizophrenia; (ii) provide effective, timely treatment and rehabilitation; (iii) improve patients' psychiatric symptoms and cognitive impairment; (iv) promote healthy behavior in the general population and emphasize healthy lifestyles in vulnerable populations; and (v) remove the stigma of schizophrenia. To reduce disparities in physical health, public health strategies and welfare policies must continue to focus on this group of patients.