Genetic polymorphisms in cytochrome P450 and clinical outcomes of FOLFIRI chemotherapy in patients with metastatic colorectal cancer

CYP3A5 Polymorphism in Circulating Tumor Cells Confers an Increased Disease-Free Survival in DLBCL Patients Treated with R-CHOP

Purpose

Diffuse Large B-Cell Lymphoma (DLBCL) is a heterogeneous aggressive lymphoid neoplasm. Cases of refractoriness and relapse persist in approximately 40% of patients treated with first-line R-CHOP regimen, thus, the identification of factors associated with disease progression have become a necessity. Diverse polymorphisms in genes encoding proteins involved in the metabolism and elimination of chemotherapeutic drugs have been studied as potential causes of treatment failure. In oncology, liquid biopsies have emerged as a non-invasive method for detecting circulating biomarkers, thereby strengthening both diagnosis and prognosis for patients. Therefore, the purpose of this study was to determine polymorphisms in Circulating Tumor Cells (CTCs) to describe the relevance of liquid biopsy in the clinical outcomes of patients with DLBCL.

Patients and Methods

We analyzed 102 liquid biopsies of peripheral blood from DLBCL patients, of which CTCs were isolated by density gradient and CD20 immunomagnetic antibodies. Allelic discrimination assays were performed to analyze ABCB1 C3435T, ABCG2 C421A and CYP3A5 A6986G polymorphisms. Overall survival (OS) and disease-free survival (DFS) analysis were performed using Kaplan-Meier curves and risk analysis was performed using Cox regression.

Results

We found that GG genotype of CYP3A5 A6986G was associated with a longer DFS (68.6% vs 49%, p=0.019) and lower risk of course with adverse event related to disease (progression, relapse and death) (OR 0.374, CI 0.187-0.745, p=0.011). No significant associations were found between ABCB1 C3435T and ABCG2 C421A genotype with the clinical outcome.

Conclusion

In this study, we demonstrated that in CTCs derived from liquid biopsies, the GG genotype in the CYP3A5 A6986G, which is related to the metabolism and elimination of chemotherapy drugs, impacts in longer DFS. These findings confirm the relevance of circulating biomarkers in non-invasive biological samples for strengthening the prognosis of DLBCL.

Predicting drug response and toxicity in metastatic colorectal cancer: the role of germline markers

INTRODUCTION

Despite the introduction of targeted agents leading to therapeutic advances, clinical management of patients with metastatic colorectal cancer (mCRC) is still challenged by significant interindividual variability in treatment outcomes, both in terms of toxicity and therapy efficacy. The study of germline genetic variants could help to personalize and optimize therapeutic approaches in mCRC.

AREAS COVERED

A systematic review of pharmacogenetic studies in mCRC patients published on PubMed between 2011 and 2021, evaluating the role of germline variants as predictive markers of toxicity and efficacy of drugs currently approved for treatment of mCRC, was perfomed.

EXPERT OPINION

Despite the large amount of pharmacogenetic data published to date, only a few genetic markers (i.e., DPYD and UGT1A1 variants) reached the clinical practice, mainly to prevent the toxic effects of chemotherapy. The large heterogeneity of available studies represents the major limitation in comparing results and identifying potential markers for clinical use, the role of which remains exploratory in most cases. However, the available published findings are an important starting point for future investigations. They highlighted new promising pharmacogenetic markers within the network of inflammatory and immune response signaling. In addition, the emerging role of previously overlooked rare variants has been pointed out.

Quality Control Measures and Validation in Gene Association Studies: Lessons for Acute Illness

Acute illness is a complex constellation of responses involving dysregulated inflammatory and immune responses, which are ultimately associated with multiple organ dysfunction. Gene association studies have associated single-nucleotide polymorphisms (SNPs) with clinical and pharmacological outcomes in a variety of disease states, including acute illness. With approximately 4 to 5 million SNPs in the human genome and recent studies suggesting that a large portion of SNP studies are not reproducible, we suggest that the ultimate clinical utility of SNPs in acute illness depends on validation and quality control measures. To investigate this issue, in December 2018 and January 2019 we searched the literature for peer-reviewed studies reporting data on associations between SNPs and clinical outcomes and between SNPs and pharmaceuticals (i.e., pharmacogenomics) published between January 2011 to February 2019. We review key methodologies and results from a variety of clinical and pharmacological gene association studies, including trauma and sepsis studies, as illustrative examples on current SNP association studies. In this review article, we have found three key points which strengthen the potential accuracy of SNP association studies in acute illness and other diseases: providing evidence of following a protocol quality control method such as the one in Nature Protocols or the OncoArray QC Guidelines; enrolling enough patients to have large cohort groups; and validating the SNPs using an independent technique such as a second study using the same SNPs with new patient cohorts. Our survey suggests the need to standardize validation methods and SNP quality control measures in medicine in general, and specifically in the context of complex disease states such as acute illness.

HSPB1 rs2070804 polymorphism is associated with the depth of primary tumor

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer in the world. Genome-wide association studies are a powerful method to analyze the status of single-nucleotide polymorphisms (SNPs) in specific genes. Heat shock proteins (HSPs) were found to be involved in the cancer progression and chemoresistance. However, there is still no further study about polymorphisms of HSP beta-1 (HSPB1) in colorectal cancer. We proposed the SNP of HSPB1 may be correlated with the progression and metastasis in colon cancer.

METHODS

We recruited 379 colorectal cancer patients and categorized as four stages following the UICC TNM system. Then, we selected tagging SNPs of HSPB1 by 10% minimum allelic frequency in Han Chinese population from the HapMap database and analyze with the Chi-square test.

RESULTS

We demonstrated the association of HSPB1 genetic polymorphisms rs2070804 with tumor depth with colorectal cancer. But, there is a lack of association between HSPB1 genetic polymorphisms and colorectal cancer invasion, recurrence or metastasis.

CONCLUSIONS

The polymorphisms of HSPB1 seemed to change the tumor behavior of colorectal cancer. HSPB1 rs2070804 polymorphism is associated with the depth of the primary tumor. But, there is no further correlation with other to the clinical parameters such as cancer invasiveness, local recurrence, or distant metastasis.

Tumor response to irinotecan is associated with CYP3A5 expression in colorectal cancer

Recently, a tumor-autonomous cytochrome P450 (CYP)-3A5-mediated resistance to cancer therapy has been demonstrated in pancreatic ductal adenocarcinoma. Expression of CYP3A5, which is involved in the degradation of irinotecan, has also been reported in colorectal cancer (CRC). The aim of the present study was to analyze CYP3A5 expression in the normal colon, colon adenoma, CRC and normal tissues, as well as to examine whether CYP3A5 expression in CRC has an impact on tumor response to irinotecan treatment. Immunohistochemistry was used to assess 85 tissue samples from 65 patients with CRC, along with 15 samples of normal colon and 45 samples of colon adenoma (including tubular, tubulovillous, and sessile serrated adenomas), and a tissue microarray (TMA) comprised of 26 different normal tissue types. Expression of CYP3A5 was evaluated with a semi-quantitative score. Tumor response to irinotecan therapy was assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 guidelines. In normal tissues, CYP3A5 was expressed in epithelial cells of the colon, gallbladder, kidney, liver, small intestine, stomach, thyroid gland and tonsil, as well as in nerves. Expression in colon mucosa was heterogeneous, with only weak staining in the minority of specimens. CYP3A5 exhibited markedly higher expression in adenomas compared with normal colon tissues. A statistically significant inverse correlation was identified between CYP3A5 expression in CRC tissues and tumor response to irinotecan therapy. Irinotecan treatment itself did not alter CYP3A5 expression in CRC tissues. As CYP3A5 is involved in the degradation of irinotecan, the significantly higher intratumoral expression of CYP3A5 in patients with CRC who do not respond to irinotecan-based chemotherapy may indicate a causal role of CYP3A5 in tumor resistance.