Genetic predisposition to cancer

The influence of an IL-4 variable number tandem repeat (VNTR) polymorphism on breast cancer susceptibility

Backgrounds

Breast cancer (BC) is one of the most widespread cancers globally. Understanding the etiology of BC may help in determining the various risk factors involved in its malignancy. Certain genetic mutations are considered to play a key role in increasing the risk of BC.

Objectives

In this study, we explored the correlation between a variable number tandem repeat (VNTR) polymorphism in the IL-4 gene and BC.

Methods

PCR and subsequent gel electrophoresis were used to genotype this variant in 360 Jordanian women (180 BC patients and 180 controls). In addition, phenotype–genotype analysis was carried out.

Results

Our findings illustrate that there is no significant relationship between the variant genotypes in the IL-4 gene and BC among Jordanian females. Other than body mass index and tumor differentiation (p< 0.05), none of the clinical and pathological parameters of BC patients exhibited any association with the variant genotypes.

Conclusions

From this study, we propose that the IL-4 genetic variant does not impact BC development and progression but that it could influence the disease prognosis.

Characterization of Copy Number Variations in Oral Cavity Squamous Cell Carcinoma Reveals a Novel Role for MLLT3 in Cell Invasiveness

BACKGROUND

DNA copy number variations (CNVs) are a hallmark of cancer, and the current study aimed to demonstrate the profile of the CNVs for oral cavity squamous cell carcinoma (OSCC) and elucidate the clinicopathological associations and molecular mechanisms of a potential marker derived from CNVs, mixed-lineage leukemia translocated to chromosome 3 protein (MLLT3), in OSCC carcinogenesis.

MATERIALS AND METHODS

CNVs in 37 OSCC tissue specimens were analyzed using a high-resolution microarray, the OncoScan array. Gene expression was analyzed by real-time polymerase chain reaction in 127 OSCC and normal tissue samples. Cell function assays included cell cycle, migration, invasion and chromatin immunoprecipitation assays.

RESULTS

We found a novel copy number amplified region, chromosome 9p, encompassing MLLT3 via the comparison of our data set with six other OSCC genome-wide CNV data sets. MLLT3 overexpression was associated with poorer overall survival in patients with OSCC (p = .048). MLLT3 knockdown reduced cell migration and invasion. The reduced invasion ability in MLLT3-knockdown cells was rescued with double knockdown of MLLT3 and CBP/p300-interacting transactivator with ED rich carboxy-terminal domain 4 (CITED4; 21.0% vs. 61.5%). Knockdown of MLLT3 impaired disruptor of telomeric silencing-1-like (Dot1L)-associated hypermethylation in the promoter of the tumor suppressor, CITED4 (p < .001), and hence dysregulated HIF-1α-mediated genes (TWIST, MMP1, MMP2, VIM, and CDH1) in OSCC cells.

CONCLUSION

We identified unique CNVs in tumors of Taiwanese patients with OSCC. Notably, MLLT3 overexpression is related to the poorer prognosis of patients with OSCC and is required for Dot1L-mediated transcriptional repression of CITED4, leading to dysregulation of HIF-1α-mediated genes.

IMPLICATIONS FOR PRACTICE

This article reports unique copy number variations in oral cavity squamous cell carcinoma (OSCC) tumors of Taiwanese patients. Notably, MLLT3 overexpression is related to the poorer prognosis of patients with OSCC and is required for Dot1L-mediated transcriptional repression of CITED4, leading to dysregulation of HIF-1α-mediated genes.

Outcomes of oral squamous cell carcinoma in Taiwan after surgical therapy: factors affecting survival

PURPOSE

The study goal was to determine which clinical features correlated with 5-year survival in patients surgically treated for oral squamous cell carcinoma (OSCC) in Taiwan.

PATIENTS AND METHODS

The records of 378 OSCC patients surgically treated with or without chemotherapy and radiotherapy were reviewed retrospectively. Their 5-year survival in relation to age, gender, tumor site, lymph node involvement, presence of distant metastasis, staging, differentiation, and risk factors, including betel quid (BQ) chewing, cigarette smoking, and alcohol consumption, was analyzed.

RESULTS

The majority of the patients were men (male-to-female ratio, 5.87:1) with the mean age of 57.1 +/-11.7 years. Tumors occurred mainly at the buccal mucosa (BM) (100 of 378, 26.5%), gingiva (105 of 378, 27.8%), and tongue (103 of 378, 27.2%). Neck nodal metastasis occurred frequently at the floor of the mouth (in >60% of cases), followed by the gingiva (45.7%), buccal mucosa (34%), and tongue (20.4%), whereas early distant metastasis was rare (5.3%). There were 104 (27.5%) stage 1, 96 (25.4%) stage 2, 98 (25.9%) stage 3, and 80 (21.2%) stage 4 patients. OSCC at the BM and gingiva was most (and at the tongue least) associated with risk factors of BQ use and smoking. The 5-year survival was 75%, 65.6%, 49%, and 30% for patients with stage I, II, III, and IV, respectively. The size, nodal involvement, distant metastasis, staging, differentiation, and BQ use significantly affected the survival (P <.05, Kaplan-Meier analysis). BQ use also correlated most significantly with the younger age of occurrence of OSCC patients.

CONCLUSIONS

Our data suggest that early treatment is the key to increasing the survival of OSCC patients. Periodic screening of high-risk populations for OSCC represents an urgent need in Taiwan.

Genetic polymorphism of cytochrome P4501A1 and susceptibility to oral squamous cell carcinoma and oral precancer lesions associated with smoking/betel use

BACKGROUND

The importance of the CYP1A1 polymorphisms at exon 7 (Ile/Val) and 3'-untranslated region (3'-UTR) has been controversial in oral squamous cell carcinoma (OSCC) or head and neck SCC (HNSCC) denoting the value of exploring the correlation between these polymorphisms and risk of betel/smoking associated OSCC. It is also important to evaluate the association between CYP1A1 polymorphisms and susceptibility of oral precancerous lesion (OPL) to confirm the findings in OSCC cases.

METHODS

We examined polymorphic prevalence of CYP1A1 at exon 7 (Ile/Val) and 3'-UTR in 106 cases with OSCC, 60 cases with OPL, and 146 controls. DNA isolated from surgical specimens and whole blood was used for PCR-based genotyping.

RESULTS

The prevalence of the CYP1A1 A/G genotype (Ile/Val) and G/G genotype (Val/Val) in exon 7 of cases with OSCC (79.2 and 7.6%) and OPL (68.3 and 10%) were significantly higher than in controls (53.4 and 1.4%) (P < 0.0001). The novelty of the present study is that we identified the onset age of OSCC in CYP1A1 A/G genotype to be significantly younger than that in A/A genotype (P < 0.01). No significant difference was seen between cases and controls regarding the polymorphisms at 3'-UTR.

CONCLUSION

The findings indicate that the individuals with the CYP1A1 exon 7 containing G allele were at increased risk for OSCC and OPL.

Distinct chromosomal deleted regions defining different subsets of head and neck tumors

The aim of this work is detecting the loss of heterozygosity (LOH) and its relationship with the development and progression of head and neck cancer. Matched normal and tumor DNA from 81 patients with head and neck cancer were examined for LOH using six microsatellite repeat markers mapped to chromosomal regions 3p13, 6q13, 9p21, 11p15, 17p13.1, and 17q22. LOH frequency at a locus ranged from 21% to 55%. The highest frequencies were at 3p (41%), 9p (48%), and 17p (54%). Thirty-two of 81 tumor samples showed allelic loss at more than one region. Significant associations were found between LOH at 3p and 9p (P = 0.001), 9p and 11p (P = 0.03), and 9p and 17p (P = 0.007). LOH at 11p was frequent in tumors from the oral cavity (5/17), oropharynx (2/7), and hypopharynx (5/10), but absent in tumors from the larynx (0/11) (P = 0.02), and LOH at 17q was observed in tumors from oral cavity (10/30) and hypopharynx (3/9), but not in tumors from the oropharynx (0/10) or larynx (0/13) (P = 0.003). In addition to that, the occurrence of allelic losses at 9p and 17p strongly correlates to tobacco smoking (P = 0.03 and P = 0.006, respectively) and alcohol intake (P = 0.01 and P = 0.005, respectively). These results suggest that tumors from different sites have different LOH patterns and corroborate with epidemiological data implicating tobacco and alcohol in the etiology of head and neck tumors.

Environment and cancer: who are susceptible?

Acting in concert with individual susceptibility, environmental factors such as smoking, diet, and pollutants play a role in most human cancer. However, new molecular evidence indicates that specific groups-characterized by predisposing genetic traits or ethnicity, the very young, and women-may have heightened risk from certain exposures. This is illustrated by molecular epidemiologic studies of environmental carcinogens such as polycyclic aromatic hydrocarbons and aromatic amines. Individual genetic screening for rare high-risk traits or for more common, low-penetrant susceptibility genes is problematic and not routinely recommended. However, knowledge of the full spectrum of both genetic and acquired susceptibility in the population will be instrumental in developing health and regulatory policies that increase protection of the more susceptible groups from risks of environmental carcinogens. This will necessitate revision of current risk assessment methodologies to explicitly account for individual variation in susceptibility to environmental carcinogens.

Detrimental effects of perioperative blood transfusion

Evidence suggests that perioperative allogeneic blood transfusion increases the risk of infectious complications after major surgery and of cancer recurrence after curative operation. This has been attributed to immunosuppression. Several authors have suggested that filtered whole blood and/or red cell concentrate, or leucocyte- and buffy coat-reduced red cells in artificial medium or their own plasma, may reduce postoperative immunosuppression. It was also anticipated that the use of autologous blood might minimize the risk of perioperative transfusion, but studies have unexpectedly shown similar postoperative infectious complications and cancer recurrence and/or survival rates in patients receiving autologous blood donated before operation and those receiving allogeneic blood. Future studies should identify common risk factors associated with blood storage.

Molecular biology and the radiation oncologist

An overview is provided of several recent advances in our understanding of the molecular events that occur when cells are exposed to ionizing radiation. A basic knowledge of molecular radiobiology is necessary so that the radiation oncologist can (i) screen cancer patients for an abnormally reduced or exaggerated response to radiotherapy; and (ii) devise novel ways to counter the molecular pathways that sustain malignant progression.

Ovarian cancer and ABO blood groups

OBJECTIVE

To determine whether the distribution of ABO blood groups in women with ovarian cancer differs from that in the general population in a large, defined English region.

DESIGN

Analysis of record abstracts of hospital care held in the Oxford record linkage study supplemented with data from the Oxford cancer registry.

SETTING

Oxford Regional Health Authority area.

SUBJECTS

A total of 1261 women who had ovarian cancer between 1968 and 1986 with ABO blood groups recorded on the Oxford Record Linkage Study and cross checked against the cancer registry comprised the study group.

MEASUREMENTS AND MAIN RESULTS

The relative incidence of A:O and B:O blood groups in women with ovarian cancer were compared with the general population in the same region. Ovarian cancer was more common in women of blood group A than in others, with a relative incidence of 1.17. In particular, adenocarcinomas were the most common type of tumour and were associated with blood group A. The association was more striking in married women than in single women probably reflecting differences associated with parity.

CONCLUSION

The association between ABO blood groups and ovarian cancer found in this English population is similar in size to that reported from several other populations. Childbearing is known to reduce the risk of ovarian cancer and our findings suggest that the blood group association may be most apparent in married, parous (that is, relatively low risk) women.

Linkage to markers for the chromosome region 17q12-q21 in 13 Dutch breast cancer kindreds

We have performed linkage analysis with five markers for the chromosome region 17q12-q21 in 13 Dutch breast cancer kindreds in order to find support for the claim by Hall et al. that a gene in this region, termed "BRCA1," is associated with predisposition to early-onset familial breast cancer. This work is part of a collaborative study, the results of which are published elsewhere in this issue. Best evidence for linkage was observed with the marker CMM86 (D17S74) in pedigrees with an average age at onset of < or = 47 years (LOD score = 1.77 at 1% recombination). In one breast-ovarian cancer family with a high probability of being linked to 17q, we observed one putative recombinant between D17S250 and D17S579, which suggests that BRCA1 is proximal to D17S579.

Ovarian and cervical cancer

Death rates from cervical cancer have already fallen this century and for patients with invasive cervical cancer five year survival rates are greater than for most solid tumours. Better screening for premalignant changes may further reduce the incidence of invasive cancer; indeed, it has been claimed that the reduction in mortality could be as high as 90%, though estimates of screening efficacy have varied greatly. For those with advanced invasive carcinoma neoadjuvant chemotherapy may reduce the risk of relapse and improve survival.