Oral carcinogenesis and non-invasive biomarkers for the diagnosis of oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most prevalent cancer in Pakistani population because of consumption of different tobacco-containing products whether smoked or chewed. These patients commonly report at a late stage of the disease. The patient's survival only depends upon early-stage diagnosis. Literature has reported that there is an increased tendency of transformation of oral potentially malignant disorder (OPMD) into OSCC. Biopsy is the gold standard measure for diagnosis but for OPMD cases biopsy was not recommended and most of the times the patients were also not willing to have a biopsy done. So, along with the biopsy there is a need for non-invasive protein biomarker that might aid in the early detection of oral cancer as well as highlight the high-risk individuals. This short communication focuses on the role of early diagnostic biomarkers present in literature, such as synuclein-γ (SNCG), Squamous cell carcinoma antigen (SCCAg), p53, MMPs-12, and IL-6. Furthermore, application of these biomarkers in multi-centre longitudinal studies is needed to establish their role as a non-invasive diagnostic biomarker for OSCC.

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

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. METHODS: 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 B 8(80%). CONCLUSIONS: Intra-ethnic distribution of tobacco-metabolising enzyme genes can be considered an important contributor to oral cancer risk in the population of Karachi.

Gene-gene and gene-environment interaction: An important predictor of oral cancer among smokeless tobacco users in Karachi.

OBJECTIVE: To determine the risk for oral cancer caused by simultaneous occurrence of more than one of the tested cytochrome P450 CYP1A1 MspI, glutathione S-transferase M1 null gnd Glutathione S-transferases T1 null gene polymorphisms. METHODS: The cross-sectional case-control study was conducted from December 2011 to October 2016 at the Ziauddin University, Karachi, in collaboration with Dow University of Health Sciences, Karachi, and comprised oral squamous cell carcinoma cases in group A and healthy tobacco habit-matched controls in group B. All investigations were done using standardised laboratory protocols. The outcomes were determined in terms of association of various combinations of cytochrome P450 1A1MspI, glutathione S-transferasesM1 null and glutathione S-transferases T1 null polymorphisms with oral cancer. Data was analysed using SPSS 20. RESULTS: Of the 238 subjects, 140(58.8%) were in group A and 98(41.2%) were in group B. Mean ages in group A and B were 47.1±12.22 and 41.6±14.58 years, respectively. Male/Female ratio in group A was 1.88:1 while 83.4% were using tobacco. When cytochrome P450 1A1MspI homozygous (m2/m2) and glutathione S-transferases M1 null variants occured simultaneously in an individual, an odds ratio of 12.8 (95% confidence interval: 1.20-135.5; p=0.03) among overall tobacco chewers was observed. For glutathione S-transferases M1 not null and glutathione S-transferases T1 null variant combination among overall tobacco users, the conferred odds ratio was 4.58 (95% confidence interval: 0.99-21.2; p=0.05). The other studied gene combinations did not reveal significant associations (p>0.05). CONCLUSIONS: A higher risk of oral squamous cell carcinoma was found to be associated with combined-gene polymorphisms of phase I and phase II enzymes than that attributed to a single-gene polymorphism.

Life-time tobacco consumption and oral cancer among citizens of a high incidence metropolis.

OBJECTIVE: To analyse dose-response relationship between the common risk factor of tobacco consumption and oral lesions like squamous cell carcinoma and pre-cancerous lesions. METHODS: The cross-sectional case-control study was conducted at Ziauddin University, Karachi from 2011 to 2016, and comprised histologically-confirmed cases of oral squamous cell carcinoma in group A, clinically-diagnosed oral pre-cancerous lesions in group B, and habit-matched controls in group C. The subjects were enrolled from 2011 to 2016. Life-time tobacco exposure was calculated using chewing index and smoking index for comparison between cases and controls. Data was analysed using SPSS 20. RESULTS: Of the 358 subjects, 150(42%) were in group A with a mean age of 47.1±12.22 years, 100(28%) were in group B with a mean age of 34.17±13.78 years, and 108(30%) were in group C with a mean age of 41.6±14.58 years. Of all the group A patients, 125(83.33%) and 96(96%) in group B had a positive history of tobacco use, with tobacco-chewers being the most in numbers 172(68.8%). Exclusive smoking was seen in 11(4.4%) cases, 38(15.2%) patients were both tobacco-chewers and smokers, and 29(11.6%) were tobacco-free. Group A and B patients had life-time tobacco exposures either equal or lower compared to group C controls (p>0.05). CONCLUSION: Life-time tobacco exposure indices were either comparable or lower in patients compared to the controls.

Conventional clinical and prognostic variables in 150 oral squamous cell carcinoma cases from the indigenous population of Karachi.

OBJECTIVE: To analyze clinical and prognostic variables of Oral Squamous Cell Carcinoma (OSCC) cases from the indigenous population of Karachi and to correlate with the common risk factor of tobacco habit. METHODS: The study was conducted at Ziauddin University, Karachi. One hundred fifty OSCC cases were collected from the Oncology Department of Ziauddin University Hospital, North Nazimabad, Karachi and Otolaryngology ward of Civil Hospital, Karachi, during 2011 and 2015. The reporting included demographic details and variables like intra-oral subsites, clinical stage and histological grade. Recurrence of tumor after initial resection was also documented. RESULTS: The patient's population comprised of 98 males and 52 females. The mean age was 47.1± 12.22 (range:20-78 years). Maximum numbers were seen in the 41-50 years age group. Urdu-speaking community was the most affected ethnic group (n=75). Clinico-pathological analysis revealed that majority of cases were moderately differentiated (59%) and were either clinical stage II (35%) or IV (29%) tumors. The most common intra-oral subsite came out to be buccal mucosa of cheeks (56%) followed by lateral borders of tongue (21%), lips (13%), alveolar (6%), palate (2.6%) floor of mouth (1.3%), etc. Recurrence was observed in 08 out of 150 cases. All patients underwent primary resection±neck dissection and reconstruction where possible. CONCLUSIONS: Overall experience with oral squamous cell carcinoma shows that it has a high tendency for local invasion as well as dissemination to regional lymph nodes, i.e. cervical lymph nodes, both are associated with a poor prognosis. Preventable risk factor of tobacco chewing has been observed in majority of these cases.