Genetic profiles of different ethnicities living in Karachi as regards to tobacco-metabolizing enzyme systems and the risk of oral cancer

Abstract

Objective: To detect polymorphisms of CYP1A1, GSTM1 and GSTT1 gene loci among various tobacco-consuming ethnicities in an urban centre, and to relate these with susceptibility to oral cancer. Method: The cross-sectional, case-control study was conducted at Ziauddin University, Karachi, and the Dow University of Health Sciences, Karachi, from 2011 to 2016, and comprised patients having oral squamous cell carcinoma in group A, with oral precancerous lesions in group B, and tobacco habit-matched controls in group C. Routine histopathology was followed by molecular analysis through polymerase chain reaction and polymerase chain reaction-restriction fragment length polymorphism techniques. Data was analysed using SPSS 20. Results: Of the 358 subjects, 150(42%) were in group A, 100(28%) in group B, and 108(30%) in group C. There were 190(53.1%) Urdu-speaking subjects, 42(11.7%) Memoni-speaking, 37(10.3%) Sindhi-speaking, 34(9.5%) Balochi-speaking, 25(7%) Pashto-speaking, 15(4.2%) Punjabi-speaking, and 15(4.2) of other ethnicities. Among the Urdu-speaking ethnicity, CYP1A1 MspI heterozygous variant was the most prevalent genotype ingroup A 50(66.7%), group B 37(62.7%) and group C 36(64.3%). The homozygous variant was equally distributed in group A 8(13.5%) and group B 10(13.3%), while it remained quite low in group C 4(7.1%). Homozygous genotype was most common in Pashto-speaking subjects in group A 4(57.1%). In Urdu-speaking subjects, GSTM1-null genotype was mostly found in group B 19(32.2%), while GSTT1-null genotype was most common in group A 12(16%). Other than Urdu-speaking, GSTM1-null variant was most frequent in Sindhi-speaking subjects in group 2 8(80%). ---Continue

Exploring the Risk Factors for Oral Cancer in Pakistan: A Systematic Literature Review

“…Another factor to consider is that Pakistan is a multi-ethnic country, and the distribution of tobacco-metabolising enzymes also varies significantly among different populations [26]. More research needs to be conducted on the genetic predilection of Pakistanis to the disease and oral surgeons should practice extreme vigilance.…”

“…The risk was significantly higher than when any of these genotypes were present individually. Another study conducted by Alamgir et al [26] found that the distribution of tobacco-metabolising enzymes varied amongst populations of different ethnicities.…”

“…This review included 20 studies conducted in Pakistan. In total, 13 [15,17,[20][21][22][24][25][26][27][28][29][30][31]] of the studies were conducted in Karachi, whereas 7 [10,14,16,18,19,23,32] were carried out in different cities such as Peshawar, Islamabad, Hyderabad, and Lahore. For six of the included studies, the main aim was not to explore any or all risk factors for oral cancer; however, they collected adequate information on the topic to warrant inclusion.…”