The earlier age of onset of malignancy in developing world is related to overall infection burden and could be due to the effect on telomere length P. S. R. K. Sastry, 1 Purvish Parikh 2 1 Consultant Medical Oncologist and Bone Marrow Transplant Physician, Jaslok Hospital and Research Centre, Mumbai, India; 2 Consultant Medical Oncologist and Additional Professor of Oncology, TATA memorial Hospital, Mumbai, India Summary It is a common observation that many common cancers occur at a younger age in developing countries, like India. The cancer registry data provide incidence rate of different cancers, which suggest the same. Telomere shortening is involved in ageing of cells. Inflammation and infection result in telomere shortening in immune cells. The higher infection burden in developing countries might mean an earlier ageing of immune cells, resulting in decreased efficiency of immune surveillance and thus predisposing to cancer at an earlier age than seen in developed countries with lesser infection burden. ª 2003 Elsevier Science Ltd. All rights reserved. BACKGROUND It has been observed by many practising oncologists in India, which is a developing country, that there is dif- ference in the age of onset reported in western literature and that observed by them in practice. If a particular cancer is reported to occur most commonly in western literature at a particular age usually it is observed roughly a decade earlier in India. Though there are no national statistics available regarding cancer in India, the hospital-based cancer registries provide the following details. Data from Kolkata suggest that maximum number of cancer cases were observed in the truncated age group of 35–64 years of which 62.27% were males and 71.25% were females. If individual cancers, like lung cancer are taken in to account 50% are in the truncated age group of 45–64 years (all-India). Also a disease, like myeloid leukemia which is predominantly a disease of the elderly the statistics are as follows: 56.69% of pa- tients are in the age group of 0–44 years of age. In case of carcinoma of colon 67.34% of patients are in the age group of 0–64 of which 16.71% are in the age group of 0–44 years. Prostate cancer incidence in the age group of 0–64 years is 20.65%. A disease, like CLL which is con- sidered a disease of elderly the highest incidence is in the age group of 40–60 (55%), compared to 38% in above 60 age group. Thus even diseases which are seen predominantly in the elderly age group seem to have a higher incidence in a younger age group (1). Eukaryotic chromosomes end with telomeres, which comprise tandem repeats of the sequnce TTAGGG ex- tending over several kilobases (kb), and are involved in the stabilisation of chromosomal ends. At mitosis, like other chromosomal regions, telomeres are replicated by DNA polymerase. However, because DNA polymerase Medical Hypotheses (2003) 60(4), 573–574 ª 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0306-9877(03)00030-6 573 Received 26 June 2002 Accepted 11 November 2002 Correspondance to: Dr. P.S.R.K. Sastry, Consultant Medical Oncologist and Bone Marrow Transplant Physician, Jaslok Hospital and Research Centre, 15, D.G. Deshmukh Marg (Pedder Centre), Mumbai, India. Phone: +91 22 511 4615; Fax: +91 22 495 0508; E-mail: psrksastry2000@yahoo.com