Targeting inflammatory pathways for prevention and therapy of cancer: short-term friend, long-term foe.

Chronic infections, obesity, alcohol, tobacco, radiation, environmental pollutants, and high-calorie diet have been recognized as major risk factors for the most common types of cancer. All these risk factors are linked to cancer through inflammation. Although acute inflammation that persists for short-term mediates host defense against infections, chronic inflammation that lasts for long term can predispose the host to various chronic illnesses, including cancer. Linkage between cancer and inflammation is indicated by numerous lines of evidence; first, transcription factors nuclear factor-kappaB (NF-kappaB) and signal transducers and activators of transcription 3 (STAT3), two major pathways for inflammation, are activated by most cancer risk factors; second, an inflammatory condition precedes most cancers; third, NF-kappaB and STAT3 are constitutively active in most cancers; fourth, hypoxia and acidic conditions found in solid tumors activate NF-kappaB; fifth, chemotherapeutic agents and gamma-irradiation activate NF-kappaB and lead to chemoresistance and radioresistance; sixth, most gene products linked to inflammation, survival, proliferation, invasion, angiogenesis, and metastasis are regulated by NF-kappaB and STAT3; seventh, suppression of NF-kappaB and STAT3 inhibits the proliferation and invasion of tumors; and eighth, most chemopreventive agents mediate their effects through inhibition of NF-kappaB and STAT3 activation pathways. Thus, suppression of these proinflammatory pathways may provide opportunities for both prevention and treatment of cancer.

Prognostic importance of DNA repair gene polymorphisms of XRCC1 Arg399Gln and XPD Lys751Gln in lung cancer patients from India.

PURPOSE: Inter individual variation in lung cancer susceptibility may be modulated in part through genetic polymorphisms in the DNA repair genes, especially the genes involved in the Base Excision Repair (BER) and nucleotide excision repair (NER) pathway. Two of the genetic polymorphisms, XRCC1Arg399Gln and XPD Lys751Gln have been extensively studied in the association with lung cancer risk, although published studies have been inconclusive. METHODS: In order to verify the role of the common variant alleles in the XPD gene, we have genotyped 211 lung cancer patients and 211 healthy controls using PCR-RFLP assays in a hospital based, case-control study in an Indian population. Logistic regression models were fit to examine the relationship between the log odds of lung cancer and each covariate. Overall Survival in relation to various genotypes and clinicopathological factors were analyzed using Kaplan Meier estimates and hazard ratios were calculated using Cox Regression analysis. RESULTS: The carriers of XRCC1 399 AA genotypes were at higher risk of lung cancer (OR = 2.1, 95% CI:1.224-3.669, P = 0.007) than carriers of GG genotype. Subjects carrying 751 AC genotype were at an increased risk of carcinoma of the lung (OR = 1.8; 95% CI:1.233-2.807, P = 0.003) than subjects with AA genotypes. Compared to the XRCC1 399 GG/ XPD 751 AA reference genotype, the combined variants, XRCC1 399 GG/ XPD 751 AC+CC (OR = 1.9, 95% CI: 1.037-3.481), P = 0.03), XRCC1 399 GA+AA/ XPD 751 AA (OR = 1.7, 95% CI: 1.020-2.833, P = 0.04), XRCC1 399 GA+AA/XPD 751 AC+CC (OR = 2.7, 95% CI: 1.582-4.864, P = 0.01), had significantly higher odds ratios. Increasing numbers of either XPD or XRCC1 variant alleles were associated with shorter overall survival, the risk being significant for the XRCC1 gene polymorphism (P = 0.01 by log-rank test). The hazard of dying was significant for the XRCC1 399 AA genotype (HR = 3.04, 95%CI: 1.393-6.670, P = 0.005). Higher tumour stage also came out as significant predictors of patient death. CONCLUSIONS: These findings suggest that genetic polymorphisms in the DNA repair genes may modulate overall lung cancer susceptibility and that pathological stage and XRCC1 Arg399Gln independently predicted overall survival among Indian lung cancer patients.

Hereditary breast/ovarian cancer: clinicopathological characteristics and survival of BRCA2 positive and negative cases.

The clinical and pathological characteristics and prognostic outcome of patients with hereditary breast/ovarian cancer and BRCA2 mutations are poorly known. Hence, the present study aimed to correlate the BRCA2 mutation status with clinical characteristics and overall survival of 102 breast/ovarian cancer patients in Kerala, South India. All the coding regions of BRCA2 genes were PCR amplified and analyzed for mutations employing Conformation Sensitive Gel Electrophoresis and characterized by sequencing. The ORs with 95% Cls was computed to assess the association between BRCA2 gene mutation status and clinicopathologic characteristics of breast cancer patients. Survival curves were generated according to Kaplan-Meier method using Log Rank test and Cox proportional hazards regression method. Out of the 102 breast/ovarian cancer patients with known BRCA2 status, 19 were BRCA2 mutation positive. In survival analysis, BRCA2 gene mutation status (P = 0.02) and clinicopathologic parameters such as tumour size (p = 0.01), metastasis (P = 0.01), disease stage (P = 0.03) and laterality (P = 0.02) were significantly associated with poor prognosis of breast cancer patients. Patients with hereditary breast/ovarian cancer resulting from a BRCA2 mutation have been conclusively shown to have a worse survival prognosis compared to the non mutated group of patients.