Abstract. Pancreatic cancer is one of the most lethal types of cancer in the world. The incidence of pancreatic cancer increases each year with no significant decrease in mortality. Pancreatic cancer is a complex disease, and this complexity is partly attributed to late diagnosis, an aggressive phenotype, environmental factors and lack of effective treatment options. Surgical resection followed by adjuvant chemotherapy is the treatment of choice for early stage cancer, whereas gemcitabine is the standard first line therapy for patients with advanced stage disease. Treatment regimens comprising folinic acid, 5-fluorouracil, irinotecan, oxaliplatin and nab-paclitaxel have demonstrated modest effects in improving median survival rates. A number of other chemotherapeutics are currently undergoing clinical trials as components of combination therapies with gemcitabine. An increasing number of novel molecular targets and cellular pathways are being identified, which highlights the complexity of this disease. The development of chemoresistance to gemcitabine is multifactorial and there exists an interplay between pancreatic cancer cells, the tumor microenvironment and cancer stem cells. These components appear to be governed by a complex network of non-coding RNAs such as micro RNAs and long non-coding RNAs. In the present study, studies describing previous research on the understanding of the factors associated with the development of chemoresistance to gemcitabine in pancreatic cancer are reviewed. A comprehensive understanding of the multiple pathways of chemoresistance is key to develop next generation therapeutics to pancreatic cancer.

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Human papilloma virus is a causative factor in the etiology of cervical cancer with HPV16 being the most prevalent genotype associated with it. Intratype variations in oncogenic E6/E7 and capsid L1 proteins of HPV 16 besides being of phylogenetic importance, are associated with risk of viral persistence and progression. The objective of this multicentric study was to identify HPV-16 E6, E7 and L1 variants prevalent in India and their possible biological effects. Squamous cell cervical cancer biopsies were collected from 6 centres in India and examined for the presence of HPV 16. Variants of HPV-16 were characterized by full length sequence analysis of L1, E6 and E7 genes in 412 samples. Similar distribution of the variants was seen from the different centres/regions, with the European variant E350G being the most prevalent (58%), followed by American Asian variant (11.4%). Fifty six changes were seen in E6 region, 31 being nonsynonymous. The most frequent being L83V (72.3%), Q14H (13.1%) and H78Y (12.1%). Twenty-nine alterations were seen in E7 region, with 12 being nonsynonymous. The most frequent being F57V (9%). L1 region showed 204 changes, of which 67 were nonsynonymous. The most frequent being 448insS (100%), and 465delD (100%), H228D (94%), T292A (85%). The identified variants some new and some already reported can disrupt pentamer formation, transcriptional regulation of the virus, L1 protein interface interaction, B and T cell epitopes, p53 degradation, and thus their distribution is important for development of HPV diagnostics, vaccine, and for therapeutic purpose. ' UICCKey words: cervical cancer; human papilloma virus 16; variants Cervical cancer is the second most predominant cancer worldwide. 1 In India it is the most common cancer amongst women, accounting for 130,000 new cases and more than 70,000 deaths annually. Persistent infection with high risk Human papilloma virus (HPV) is the main aetiological factor in the development of cervical cancer and may depend on HPV genotypes and variants. 2 HPV-16 is the most prevalent genotype associated with cervical carcinomas globally, as well as in Indian women. [3][4][5] This could perhaps be because of differential HPV-16 variant frequency, with certain variants conferring greater oncogenecity. 6,7 The molecular variants or lineages differ in nucleotide sequence by no more than 2% in the coding region and 5% in the noncoding regions of the viral genome with respect to the prototype. 8 Through nucleotide sequence comparisons, it has been found that HPV-16 has evolved along 5 major phylogenetic branches i.e., European, Asian, Asian American, African-1 and African-2. 9 Intratypic variation of HPV-16 has been shown to be an important predictor of progression to clinical relevant cervical lesion. 10 In a cohort study of young women 16 different HPV variants were found, one of which persisted over time, although the other variants were transiently detected. 11 Considerable intratypic diversity of HPV-16 has been reported by other studies based on DNA sequenc...

Background India has a large population of HIV-positive individuals, including men who have sex with men (MSM) and the incidence of human papillomavirus (HPV)-related cancers is high. In developed countries, HIV-positive MSM exhibit the highest prevalence of anal HPV infection and incidence of anal cancer. Little is known about anal HPV infection in HIV-positive Indian MSM. Methods We evaluated 300 HIV-positive MSM from two cities in India. Men were tested for anal HPV infection using L1-HPV DNA PCR with probes specific for 29 types and a mixture of 10 additional types. CD4+ level and plasma HIV viral load were measured. Participants completed an interviewer-administered questionnaire including a sexual history. Results The prevalence of anal HPV was 95% (95% CI 91%-97%). The three most common types were HPV 35 (20%), HPV 16 (13%) and HPV 6/11 (13%). History of taking antiretroviral medications decreased risk of anal HPV 16 infection (RR: 0.6 (0.4-1.0). Having an increased number of vaginal sex partners lowered risk of any anal HPV infection. Ever having receptive sex increased risk of any anal HPV (RR: 1.2 (1.1-1.4) and anal HPV 16 (RR: 6.5 1.8-107). Conclusions Almost all Indian HIV-positive MSM had anal HPV infection. The prevalence of HPV 16 was lower and the prevalence of other oncogenic HPV types was higher than in similar populations in North America and Europe. Vaccine based prevention strategies for HPV infection in India should consider potential differences in HPV type distribution among HIV-infected MSM when designing interventions.