Prevalence of PIK3CA mutations and the SNP rs17849079 in Arab breast cancer patients

Implementation of Next-Generation Sequencing in Saudi Arabia for HER2-Positive Breast Cancer

Breast cancer is a common malignancy that poses a hazard to women's health. In 2021, around 2.3 million new cases are predicted to be discovered, with a mortality rate of 6.9% on average. Breast cancer accounts for 14.8% of malignancies among the Saudis with an 8.5% fatality rate. Breast cancers that are HER2 positive account for 15 to 20% of all breast cancers. We intended to investigate the genetic mutations and the clinicopathological aspects of HER2 positive breast cancer patients. We used TruSight Tumor 15 using Next-Generation Sequencing (NGS) to look at genetic changes in 126 Saudi women with stage I to IV breast cancer. c-MET (p = 0.001), c-KIT (p = 0.001), and PIK3CA (p = 0.0001), were shown to be substantially linked with HER2 positive patients. We also detected mutations in other genes, including BRAF, EGFR, and KRAS. Tumor size, grade, stage, and nodal status were all associated with increased levels of HER2 expression. Our results recommend that patients with HER2 positive breast cancer in Saudi Arabia have a high mutational burden, which may be related to trastuzumab resistance. We expect that in the future, targeting these mutations will be a promising therapeutic method for the treatment of breast cancer.

Molecular Spectra and Frequency Patterns of Somatic Mutations in Arab Women with Breast Cancer

BACKGROUND

The role of somatic mutations in breast cancer prognosis and management continues to be recognized. However, data on the molecular profiles of Arab women are limited.

MATERIALS AND METHODS

This was a cross-sectional study based on medical chart review of all Arab women diagnosed with breast cancer at a single institution between 2010 and 2018 who underwent next-generation sequencing with Ampliseq 46-Gene or 50-Gene.

RESULTS

A total of 78 Arab women were identified, with a median age at diagnosis of 52.3 years (range: 37-82 years; 38.5% ≤50 years). The majority of patients had stage III or IV disease (74.4%). Next-generation sequencing revealed the following somatic mutation rates: TP53, 23.1%; ATM, 2.6%; IDH1, 2.6%; IDH2, 3.8%; PTEN, 7.7%; PIK3CA, 15.4%; APC, 7.7%; NPM1, 2.5%; MPL, 1.3%; JAK2, 2.5%; KIT, 7.7%; KRAS, 3.8%; and NRAS, 3.8%.

CONCLUSION

Our study illustrates frequencies of somatic mutations in Arab women with breast cancer and suggests potential variations from estimates reported in the Western population. These data calls for larger epidemiologic studies considering the evolving role of such mutations in prognostication and personalized management.

Melittin, a honeybee venom derived peptide for the treatment of chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is the most prevalent neurological complication of cancer treatment which involves sensory and motor nerve dysfunction. Severe CIPN has been reported in around 5% of patients treated with single and up to 38% of patients treated with multiple chemotherapeutic agents. Present medications available for CIPN are the use of opioids, nonsteroidal anti-inflammatory agents, and tricyclic antidepressants, which are only marginally effective in treating neuropathic symptoms. In reality, symptom reappears after these drugs are discontinued. The pathogenesis of CIPN has not been sufficiently recognized and methods for the prevention and treatment of CIPN remain vulnerable to therapeutic problems. It has witnessed that the present medicines available for the disease offer only symptomatic relief for the short term and have severe adverse side effects. There is no standard treatment protocol for preventing, reducing, and treating CIPN. Therefore, there is a need to develop curative therapy that can be used to treat this complication. Melittin is the main pharmacological active constituent of honeybee venom and has therapeutic values including in chemotherapeutic-induced peripheral neuropathy. It has been shown that melittin and whole honey bee venom are effective in treating paclitaxel and oxaliplatin-induced peripheral neuropathy. The use of melittin against peripheral neuropathy caused by chemotherapy has been limited despite having strong therapeutic efficacy against the disease. Melittin mediated haemolysis is the key reason to restrict its use. In our study, it is found that α-Crystallin (an eye lens protein) is capable of inhibiting melittin-induced haemolysis which gives hope of using an appropriate combination of melittin and α-Crystallin in the treatment of CIPN. The review summarizes the efforts made by different research groups to address the concern with melittin in the treatment of chemotherapeutic-induced neuropathy. It also focuses on the possible approaches to overcome melittin-induced haemolysis.

Landscape of somatic mutations in breast cancer: new opportunities for targeted therapies in Saudi Arabian patients

Breast cancer (BCa) ranks first in incidence rate among cancers in Arab females. The association between genetic polymorphisms in tumor suppressor genes and the risk of BCa has been studied in many ethnic populations with conflicting conclusions while Arab females and Saudi Arabian studies are still lacking. We screened a cohort of Saudi BCa patients by NGS using a bespoke gene panel to clarify the genetic landscape of this population, correlating and assessing genetic findings with clinical outcomes. We identified a total of 263 mutations spanning 51 genes, including several frequently mutated. Among the genes analyzed, the highest mutation rates were found in PIK3CA (12.9%), BRCA2 (11.7%), BRCA1 (10.2%), TP53 (6.0%), MSH2 (3.8%), PMS2 (3.8%), BARD1 (3.8%), MLH1 (3.4%), CDH1 (3.0%), RAD50 (3.0%), MSH6 (3.0%), NF1 (2.6%), in addition to others. We identified multiple common recurrent variants and previously reported mutations. We also identified 46 novel variants in 22 genes that were predicted to have a pathogenic effect. Survival analysis according to the four most common mutations (BRCA1, BRCA2, TP53, and PIK3CA) showed reduced survival in BRCA1 and BRCA2-mutant patients compared to total patients. Moreover, BRCA2 was demonstrated as an independent predictor of reduced survival using independent Cox proportional hazard models.

We reveal the landscape of the mutations associated with BCa in Saudi women, highlighting the importance of routine genetic sequencing in implementation of precision therapies in KSA.

Targeted next generation sequencing identifies somatic mutations in a cohort of Egyptian breast cancer patients

Breast cancer (BC) incidence is progressively increasing in Egypt. However, there is insufficient knowledge of the acquired somatic mutations in Egyptian BC patients which limit our understanding of its progression. To the best of our knowledge, this is the first Egyptian cohort to sequence a multiple-gene panel of cancer related genes on BC patients. Four hundred and nine cancer related genes were sequenced in 46 fresh breast tumors of Egyptian BC patients to identify somatic mutations and their frequencies. TP53 and PIK3CA were the most top two frequently mutated genes. We detected 15 different somatic mutations in TP53 and 8 different ones in PIK3CA, each in 27 samples (58.7%). According to Clinvar database; we found 19 pathogenic somatic mutations: 7 in Tp53, 5 in PIK3CA, and single variants of VHL, STK11, AKT1, KRAS, IDH2, PTEN and ERBB2. We also identified 5 variants with uncertain significance (4 in TP53 and 1 in CEBPA) and 4 variants with conflicting interpretations of pathogenicity (2 in TP53 and 1 in each of APC and JAK3). Moreover, one drug response variant (p.P72R) in TP53 was detected in 8 samples. Furthermore, four novel variants were identified in JAK2, MTOR, KIT and EPHB. Further analysis, by Ingenuity Variant Analysis software (IVA), showed that PI3K/AKT signaling is altered in greater than 50% of Egyptian BC patients which implicates PI3K/AKT signaling as a therapeutic target. In this cohort, we shed the light on the most frequently detected somatic mutations and the most altered pathway in Egyptian BC patients.

Familial/inherited cancer syndrome: a focus on the highly consanguineous Arab population

The study of hereditary cancer, which accounts for ~10% of cancer cases worldwide is an important subfield of oncology. Our understanding of hereditary cancers has greatly advanced with recent advances in sequencing technology, but as with any genetic trait, gene frequencies of cancer-associated mutations vary across populations, and most studies that have located hereditary cancer genes have been conducted on European or Asian populations. There is an urgent need to trace hereditary cancer genes across the Arab world. Hereditary disease is particularly prevalent among members of consanguineous populations, and consanguineous marriages are particularly common in the Arab world. There are also cultural and educational idiosyncrasies that differentiate Arab populations from other more thoroughly studied groups with respect to cancer awareness and treatment. Therefore, a review of the literature on hereditary cancers in this understudied population was undertaken. We report that BRCA mutations are not as prevalent among Arab breast cancer patients as they are among other ethnic groups, and therefore, other genes may play a more important role. A wide variety of germline inherited mutations that are associated with cancer are discussed, with particular attention to breast, ovarian, colorectal, prostate, and brain cancers. Finally, we describe the state of the profession of familial cancer genetic counselling in the Arab world, and the clinics and societies dedicated to its advances. We describe the complexities of genetic counselling that are specific to the Arab world. Understanding hereditary cancer is heavily dependent on understanding population-specific variations in cancer-associated gene frequencies.

Helical and kinase domain mutations of PIK3CA, and their association with hormone receptor expression in breast cancer

Breast cancer is one of the major causes of female morbidity and mortality, accounting for ~25% of the total cancer cases in women. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic α subunit (PIK3CA) mutations serve a major role in downstream signaling of receptor tyrosine kinases. The present study aimed to elucidate the frequency of exon 9 and 20 mutations of PIK3CA and their role in disease progression. A total of 118 tumor samples from confirmed breast cancer patients were collected from the histopathology laboratory at King Fahd Hospital of the University (Al-Khobar, Saudi Arabia). Sanger sequencing was performed on extracted DNA to identify the mutations on exons 9 and 20 of PIK3CA. The results were further validated by competitive allele-specific TaqMan polymerase chain reaction. Three mutations, namely E542K and E545K within exon 9, and H1047R within exon 20, were observed in 25 patients (21.2%). Among these, 18 patients carried the H1047R mutation of the kinase domain, while the remaining 7 patients carried mutations in the helical domain. PIK3CA mutations were associated with the estrogen receptor-positive/progesterone receptor-positive (ER⁺/PR⁺) group of tumors in contrast to the ER⁻/PR⁻ group (P=0.021). Furthermore, it was observed that the PIK3CA mutation was associated with a poor disease prognosis. Taken together, the current study emphasized the potential of PIK3CA mutations as an important biomarker for breast cancer classification and the possible use of PIK3CA inhibitor as targeted therapy for breast cancer.

Association of FGFR2 and PI3KCA genetic variants with the risk of breast cancer in a Chinese population

Purpose

Genome-wide association studies have found plenty of single nucleotide polymorphisms (SNPs) which are associated with breast cancer risk. SNPs in FGFR2 are mostly identified. However, the association between PI3KCA SNP and breast cancer risk remains largely unknown. The aim of this study was to investigate the significance of FGFR2 and PI3KCA genetic variants in breast cancer and their association with prognosis.

Methods

We performed genotyping of 328 breast cancer patients and 389 healthy controls. Then, we evaluated the associations of FGFR2 rs1219648 and PI3KCA rs6443624 with the susceptibility and clinicopathological features of breast cancer. Kaplan-Meier curve with log-rank test was performed to determine the prognostic values of FGFR2 rs1219648 and PI3KCA rs6443624.

Results

The results indicated that genotype frequencies of rs1219648 and rs6443624 were significantly different between breast cancer patients and healthy controls. Furthermore, PI3KCA rs6443624 A carriers and FGFR2 rs1219648 G carriers more frequently had advanced stages and shorter survival times.

Conclusion

The SNPs of FGFR2 rs1219648 and PI3KCA rs6443624 may contribute to the identification of breast cancer patients at risk of more aggressive disease and may be potential prognostic factors in breast cancer in a Chinese population.

High prevalence of deleterious BRCA1 and BRCA2 germline mutations in arab breast and ovarian cancer patients

PURPOSE

The BRCA1 and BRCA2 (BRCA) genes are heavily involved in mammalian cell DNA repair processes. Germline pathogenic mutations in BRCA increase the lifetime risk of developing breast and/or ovarian cancer in women. In the Arabian Peninsula, most breast and ovarian cancers are diagnosed as early-onset cases, some of which may be due to germline variants in BRCA genes. To identify the BRCA germline mutation frequency and spectrum in the Arab breast and ovarian cancers, we have sequenced the protein-coding exons of these genes.

METHODS

All BRCA coding exons were sequenced using genomic DNA isolated from lymphocytes in 173 Arab breast and ovarian cancer patients by a massively parallel sequencing technology and verified by Sanger sequencing.

RESULTS

We identified a total of 17 distinct pathogenic mutations, of which four were novel, in 28 patients; nine out of 108 breast (8.3%) and 19 out of 65 ovarian cancer (29.2%) patients. Thirteen of the 17 mutations were detected in BRCA1 and four mutations were found in BRCA2 gene. Four pathogenic BRCA1 mutations (c.1140dupG, c.4136_4137delCT, c.5095C>T, and c.5530delC) accounted for 54% of all the mutations detected in our patient cohort. Additionally, we identified a likely pathogenic BRCA1 missense variant in two of 108 breast (1.9%) and a BRCA2 missense variant in one of 65 ovarian cancer (1.5%) patients.

CONCLUSIONS

The overall frequencies of the BRCA germline mutations were 10.2% in breast and 30.7% in ovarian cancer patients. These data shed new light into the prevalence of BRCA mutations in the Arab women population.

Absence of the frequently reported PIK3CA, CASP8, and NOTCH1 mutations in South Indian oral cancers

OBJECTIVES

Somatic mutations of the PIK3CA, CASP8, and NOTCH1 have been frequently detected in various human cancers. Our study aimed to analyze the mutational status of these genes in South Indian oral cancers.

SUBJECTS AND METHODS

We performed mutational analysis of the PIK3CA (exons 9 and 20), CASP8 (exon 9), and NOTCH1 (exons 5, 6, 7, 8, and 9) genes in 96, 48, and 44 oral cancer samples, respectively. All the specified exons were PCR (polymerase chain reaction)-amplified and directly sequenced by Sanger sequencing.

RESULTS

PIK3CA gene mutations were not found; however, a synonymous single nucleotide polymorphism (SNP) [rs17849079] was observed frequently [35/96 (36.4%)] in oral cancer samples. Further, no mutations were detected in the CASP8 gene, but observed a frequent [32/48 (66.6%)] SNP [rs1045487] in the oral cancer samples. We did not detect any mutation in the NOTCH1 gene (exons 5, 6, 7, 8, and 9) in all the [0/44] analyzed oral cancer samples.

CONCLUSIONS

This is the first study that reports the status of the PIK3CA, CASP8, and NOTCH1 mutations in South Indian oral cancer samples. Our study suggests that either mutations in these genes are uncommon in South Indian oral cancer samples or likely other genes in this pathway might be mutated.

Potential biomarker panels in overall breast cancer management: advancements by multilevel diagnostics

Breast cancer (BC) prevalence has reached an epidemic scale with half a million deaths annually. Current deficits in BC management include predictive and preventive approaches, optimized screening programs, individualized patient profiling, highly sensitive detection technologies for more precise diagnostics and therapy monitoring, individualized prediction and effective treatment of BC metastatic disease. To advance BC management, paradigm shift from delayed to predictive, preventive and personalized medical services is essential. Corresponding step forwards requires innovative multilevel diagnostics procuring specific panels of validated biomarkers. Here, we discuss current instrumental advancements including genomics, proteomics, epigenetics, miRNA, metabolomics, circulating tumor cells and cancer stem cells with a focus on biomarker discovery and multilevel diagnostic panels. A list of the recommended biomarker candidates is provided.

Molecular evaluation of PIK3CA gene mutation in breast cancer: determination of frequency, distribution pattern and its association with clinicopathological findings in Indian patients

Somatic mutations in the PIK3CA gene are common in breast cancer and represent a clinically useful marker for prognosis and therapeutic target. Activating mutations in the PI3K p110 catalytic subunit (PIK3CA) have been identified in 18-40 % of breast carcinomas. In this study, we evaluated PIK3CA mutation in 185 Indian breast cancer patients by direct DNA sequencing. PIK3CA mutations were observed in 23.2 % (43/185) of breast tumor samples. PIK3CA mutations were more frequent exon 30 (76.8 %) than in exon 9 (23.2 %). Mutations were mostly clustered within two hotspot region between nucleotides 1624 and 1636 or between 3129 and 3140. Sequencing analysis revealed four different missense mutations at codon 542 and 545 (E542K, E545K, E545A and E545G) in the helical domain and two different amino acid substitutions at codon 1047 (H1047R and H1047L) in the kinase domain. None of the cases harbored concomitant mutations at multiple codons. PIK3CA mutations were more frequent in older patients, smaller size tumors, ductal carcinomas, grade II tumors, lymph node-positive tumors and non-DCIS tumors; however, none of the differences were significant. In addition, PIK3CA mutations were common in ER+, PR+ and HER2+ cases (30 %), and a comparatively low frequency were noted in triple-negative tumors (13.6 %). In conclusion, to our knowledge, this is the largest study to evaluate the PIK3CA mutation in Indian breast cancer patients. The frequency and distribution pattern of PIK3CA mutations is similar to global reports. Furthermore, identification of molecular markers has unique strengths and can provide insights into the pathogenic process of breast carcinomas.

Analysis of PI3K/mTOR Pathway Biomarkers and Their Prognostic Value in Women with Hormone Receptor-Positive, HER2-Negative Early Breast Cancer

BACKGROUND: The PI3K/AKT/mTOR pathway alterations have been shown to play significant roles in the development, progression, and metastatic spread of breast cancer. Furthermore, they have been implicated in the process of drug resistance, especially endocrinal therapies. In this study, we aimed to define the correlation between the PI3K mutations and the expression of the phosphorylated forms of different downstream molecules in women with estrogen receptor (ER)–positive, human epidermal growth factor receptor 2–negative (luminal) early breast cancer treated at Cairo university hospitals. METHODS: Next-generation sequencing was used to detect mutations in the PIK3CA hotspots (in exons 9 and 20). Immunohistochemistry was performed on tissue microarray blocks prepared from samples of 35 Egyptian luminal breast cancer patients in the pathology department of Centre Léon Bérard (CLB). The intensity and the percentage of stained tumor cells were integrated to define high versus low biomarker expression. The cytoplasmic and nuclear stainings were graded separately. Patients were followed for a median of 4.7 years (2.1 to 6.9 years). Correlation was done between PI3K mutations and the immunohistochemistry expression of pAKT, LKB1, p4EBP1, and pS6 ribosomal protein (pS6RP) with the clinicopathologic features and disease free survival (DFS) of the patients. RESULTS: Median age at diagnosis was 51.3 years (range, 25 to 82 years). Tumors were larger than 20 mm in 79.2% of the cases, whereas 57.9% had axillary lymph node deposits. Only 12.3% of the patients had SBR grade I tumors, 50.8% had grade II, and 36.8% had grade III. ERs were negative in 6 patients (17%) after pathology review. Thirty-two cases were assessable for LKB1 and pAKT, 33 for p4EBP1 and pS6RP, and 24 for PI3K mutations. Nuclear LKB1, cytoplasmic LKB1, nuclear pAKT, cytoplasmic pAKT, nuclear p4EBP1, and cytoplasmic pS6RP expression was high in 65.6%, 62.5%, 62.5%, 68.8%, 42.4%, and 57.6%, respectively. PIK3CA mutations were found in 7 patients (29.2%). PI3K mutations were correlated with nuclear localization of pAKT (i.e., decreased cytoplasmic pAKT, P = .04; and increased nuclear pAKT, P = .10). There was a tendency toward an inverse correlation between PI3K mutations and the expression of pS6RP (P = .10) and p4EBP1 (P = .19). Nuclear LKB1 expression was a marker of good prognosis. It was associated with smaller tumors (P = .05), more ER (P = .08) and progesteron receptor (PgR) positivity (P = .002). In the Kaplan Meier (KM) model, patients with high nuclear LKB1 had longer DFS (hazard ratio = 0.36; 95% confidence interval, 0.15-1.10; P = .08). Nuclear pAKT high expression also carried a tendency toward longer DFS (hazard ratio = 0.51; 95% confidence interval, 0.11-1.16; P = .13). The expression of p4EBP1, pS6RP, and the PI3K mutational status did not show any prognostic significance in our cohort. CONCLUSION: Among the studied biomarkers, only nuclear expression of LKB1 and pAKT tended to predict better survival in breast cancer patients. PI3K mutation was correlated with the expression of nuclear pAKT but not pS6RP or p4EBP1.

Mutation distributions and clinical correlations of PIK3CA gene mutations in breast cancer

Breast cancer (BCa) is the most common cancer and the second cause of death among women. Phosphoinositide 3-kinase (PI3K) signaling pathway has a crucial role in the cellular processes such as cell survival, growth, division, and motility. Moreover, oncogenic mutations in the PI3K pathway generally involve the activation phosphatidylinositol-4,5-bisphosphate 3-kinase-catalytic subunit alpha (PIK3CA) mutation which has been identified in numerous BCa subtypes. In this review, correlations between PIK3CA mutations and their clinicopathological parameters on BCa will be described. It is reported that PIK3CA mutations which have been localized mostly on exon 9 and 20 hot spots are detected 25-40 % in BCa. This relatively high frequency can offer an advantage for choosing the best treatment options for BCa. PIK3CA mutations may be used as biomarkers and have been major focus of drug development in cancer with the first clinical trials of PI3K pathway inhibitors currently in progress. Screening of PIK3CA gene mutations might be useful genetic tests for targeted therapeutics or diagnosis. Increasing data about PIK3CA mutations and its clinical correlations with BCa will help to introduce new clinical applications in the near future.

Genetic association between PIK3CA gene and oral squamous cell carcinoma: a case control study conducted in Chongqing, China

PIK3CA has been shown to be involved in many malignant tumors. This study was designed to determine the expression level of PIK3CA in oral squamous cell carcinoma (OSCC) and the association of gene polymorphisms of PIK3CA with OSCC in Chinese population. The expression of PIK3CA was detected by real-time PCR in tumor and pericarcinomatous tissues of 10 OSCC patients. Nine single-nucleotide polymorphisms (SNPs) of PIK3CA (rs1607237, rs17849079, rs2677764, rs2699887, rs4855094, rs4975596, rs6443624, rs7651265 and rs7736074) in blood of 113 OSCC patients and 184 normal controls were genotyped using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) assay. The gene expression of PIK3CA was significantly higher in tumor tissues of OSCC patients than that in pericarcinomatous tissues (P = 0.012). An increased frequency of the C allele of PIK3CA rs1607237 was observed in OSCC patients as compared with controls; However, the significance was lost after Bonferroni correction (P = 0.048, pc = 0.576). In further stratification analysis, although the frequencies of PIK3CA rs4975596 A allele in male patients and rs1607237 C allele in female patients were increased (P = 0.032, P = 0.020, respectively), the significance was also missing when Bonferroni correction was performed (P c = 0.384, (P c = 0.24, respectively). The prevalence of other SNPs of PIK3CA did not differ between OSCC patients and controls. The expression of PIK3CA was increased in OSCC tumors; however, none of the nine tested SNPs of PIK3CA was associated with susceptibility to OSCC in the studied population.

Genetic variants in the inositol phosphate metabolism pathway and risk of different types of cancer

Members of the inositol phosphate metabolism pathway regulate cell proliferation, migration and phosphatidylinositol-3-kinase (PI3K)/Akt signaling, and are frequently dysregulated in cancer. Whether germline genetic variants in inositol phosphate metabolism pathway are associated with cancer risk remains to be clarified. We examined the association between inositol phosphate metabolism pathway genes and risk of eight types of cancer using data from genome-wide association studies. Logistic regression models were applied to evaluate SNP-level associations. Gene- and pathway-based associations were tested using the permutation-based adaptive rank-truncated product method. The overall inositol phosphate metabolism pathway was significantly associated with risk of lung cancer (P = 2.00 × 10⁻⁴), esophageal squamous cell carcinoma (P = 5.70 × 10⁻³), gastric cancer (P = 3.03 × 10⁻²) and renal cell carcinoma (P = 1.26 × 10⁻²), but not with pancreatic cancer (P = 1.40 × 10⁻¹), breast cancer (P = 3.03 × 10⁻¹), prostate cancer (P = 4.51 × 10⁻¹), and bladder cancer (P = 6.30 × 10⁻¹). Our results provide a link between inherited variation in the overall inositol phosphate metabolism pathway and several individual genes and cancer. Further studies will be needed to validate these positive findings, and to explore its mechanisms.

[Advancement of phenotype transformation of cancer-associated fibroblasts: from genetic alterations to epigenetic modification]

In the field of human cancer research, even though the vast majority attentions were paid to tumor cells as "the seeds", the roles of tumor microenvironments as "the soil" are gradually explored in recent years. As a dominant compartment of tumor microenvironments, cancer-associated fibroblasts (CAFs) were discovered to correlated with tumorigenesis, tumor progression and prognosis. And the exploration of the mechanisms of CAF phenotype transformation would conducive to the further understand of the CAFs function in human cancers. As we known that CAFs have four main origins, including epithelial cells, endothelial cells, mesenchymal stem cells (MSCs) and local mesenchymal cells. However, researchers found that all these origins finally conduct similiar phenotypes from intrinsic to extrinsic ones. Thus, what and how a mechanism can conduct the phenotype transformation of CAFs with different origins? Two viewpoints are proposed to try to answer the quetsion, involving genetic alterations and epigenetic modifications. This review will systematically summarize the advancement of mechanisms of CAF phenotype transformations in the aspect of genentic and epigenetic modifications.

No association between single nucleotide polymorphisms in pre-mirnas and the risk of gastric cancer in Chinese population

OBJECTIVE(S)

Accumulating evidence has demonstrated that miRNAs contribute to various genetic and epigenetic modifications in the pathogenesis of gastric cancer (GC). Recent studies focused on the four single nucleotide polymorphisms (SNPs) of pre-miRNAs including rs11614913, rs3746444, rs2910164, and rs2292832. It was suggested that these four SNPs were significantly associated with the risk of GC and were described as candidate susceptibility factors. However, the previous results show conflicting findings. The aim of this study was to investigate whether these four SNPs are associated with GC in Chinese Han population.

MATERIALS AND METHODS

Genotype frequencies of these four SNPs of pre-miRNAs in 220 GC patients and 530 control subjects were performed using a PCR-RFLP assay.

RESULTS

No significant differences in genotype and allelic distribution were found in these four SNPs between GC and control subjects in the Chinese Han population. However, we found that the allelic frequency distributions of control subjects in these four SNPs were significantly different from those of the Japanese and the Koreans (All the P<0.05).

CONCLUSION

The four SNPs did not show any significant correlation with the development of GC in the Chinese Han population, based on the current study.