Jayendra B. Patel

A Review on Salivary Genomics and Proteomics Biomarkers in Oral Cancer

Oral cancer has emerged as an alarming public health problem with increasing incidence and mortality rates all over the world. Therefore, the implementation of newer screening and early detection approaches are of utmost importance which could reduce the morbidity and mortality associated with this disease. Sensitive and specific biomarkers for oral cancer are likely to be most effective for screening, diagnosis, staging and follow-up for this dreaded malignancy. Unlike other deep cancers, oral cancer is located in oral cavity. Hence, the direct contact between saliva and oral cancer lesion makes the measurement of tumor markers in saliva an attractive alternative to serum and tissue testing. The DNA, RNA and protein molecules derived from the living cancer cells can be conveniently obtained from saliva. Thus, salivary biomarkers, a non-invasive alternative to serum and tissue-based biomarkers may be an effective modality for early diagnosis, prognostication and monitoring post therapy status. In the current post-genomic era, various technologies provide opportunities for high-throughput approaches to genomics and proteomics; which have been used to evaluate altered expressions of gene and protein targets in saliva of oral cancer patients. The emerging field of salivary biomarkers has great potentials to prove its clinical significance to combat oral cancer. Hence, we have reviewed importance of several salivary genomics and proteomics biomarkers for oral cancer.

Clinical usefulness of telomerase activation and telomere length in head and neck cancer

Telomere shortening at every replication cycle is postulated to limit the life span of human somatic cells. In contrast, activation of telomerase is proposed to be an essential step for cancer cell immortalization. Head and neck cancer is the most common malignancy in the Indian population compared with Western countries. However, there are very few reports on telomerase activity and telomere length in head and neck cancer.

Matrix Metalloproteinases and Their Inhibitors: Correlation with Invasion and Metastasis in Oral Cancer

Matrix metalloproteinases (MMPs) have been implicated in invasion and metastasis of various malignancies. The study evaluated a comprehensive profile of MMP-2 and MMP-9 and their inhibitors, tissue inhibitor of metalloproteinases-2 (TIMP-2) and tissue inhibitor of metalloproteinases-1 (TIMP-1), respectively in 50 controls and 75 patients with oral squamous cell carcinoma (OSCC). Blood samples from controls and patients as well as malignant and adjacent normal tissues from the patients were collected. The study examined pro, active and total forms of MMP-2 and MMP-9 using zymography. Enzyme-linked immunoassay (ELISA) and reverse transcription polymerase chain reaction were carried out to evaluate protein levels and mRNA expression; respectively, for the MMPs and TIMPs. Plasma pro, active and total MMP-2, MMP-9 as well as TIMP-1 and TIMP-2 levels were significantly higher in oral cancer patients as compared to the controls. mRNA expression of the MMPs and TIMPs was significantly higher in malignant tissues as compared to adjacent normal tissues. A significant positive correlation was observed between levels of proMMP-9 and active MMP-9 with differentiation, stage and infiltration. ProMMP-2 and active MMP-2 exhibited significant positive correlation with differentiation and lymph node involvement. The multivariate analysis of ELISA results revealed a significant positive correlation between MMP-2, TIMP-1 and TIMP-2 levels with lymph node involvement, stage and differentiation. The receiver operating characteristic curve (ROC) analysis showed that the levels of MMPs and TIMPs have significant discriminatory efficacy to differentiate between controls and patients. The results indicate that MMP-2, MMP-9, TIMP-1 and TIMP-2 have significant clinical usefulness for oral cancer patients. Zymographic analysis is a simple, cost effective, rapid and sensitive alternative assay.

Evaluation of serum and salivary total sialic acid and α-l-fucosidase in patients with oral precancerous conditions and oral cancer

OBJECTIVES We compared serum and salivary total sialic acid/total protein (TSA/TP) ratios and α-l-fucosidase activity in patients with oral precancerous conditions (OPCs) and oral cancer to better understand the utility of saliva, in monitoring early changes occurring during oral cancer progression. STUDY DESIGN A cross-sectional study of 100 oral cancer patients, 50 patients with OPC, and 100 controls was performed. RESULTS Serum and salivary TSA/TP ratios and α-l-fucosidase activity were significantly higher in OPC and oral cancer patients compared to the controls. Also, levels were higher in controls and oral cancer patients with tobacco habits as compared to those without tobacco habits. CONCLUSION Salivary TSA/TP ratio and α-l-fucosidase activity were elevated with higher magnitude than serum levels. These results suggest that a larger study may prove the use of these saliva biomarkers as a noninvasive method for detecting early changes occurring during oral carcinogenesis.

Association between p53 Gene Variants and Oral Cancer Susceptibility in Population from Gujarat, West India

BACKGROUND p53 gene variants i.e. 16 bp duplication in intron 3, Arg72Pro in exon 4 and G>A in intron 6 have been reported to modulate susceptibility to various malignancies. Therefore, the present study evaluated the role of these p53 polymorphisms in oral cancer susceptibility in a population from Gujarat, West India. METHOD Genotype frequencies at the three p53 loci in 110 controls and 79 oral cancer cases were determined by the PCR-RFLP method. RESULTS Heterozygous individuals at exon 4 showed protection from developing oral cancer. Homozygous wild and heterozygous individuals at intron 3 and those heterozygous at exon 4 in combination appeared to be at lowered risk. Furthermore, carriers of the 16 bp duplication allele at intron 3, proline allele at exon 4 and G allele at intron 6 were protected from oral cancer development. CONCLUSION p53 polymorphisms, especially Arg72Pro in exon 4 could significantly modify the risk of oral cancer development in Gujarat, West Indian population.

Evaluation of serum alkaline DNase activity in treatment monitoring of head and neck cancer patients.

Our previously published data on breast cancer suggest that serum alkaline DNase, a known circulating tumour marker, can be used for treatment monitoring of cancer patients. Serum alkaline DNase activities were analyzed in 215 untreated head and neck cancer patients. The enzyme activity ranged from 0.17 to 97.97 IKU/l in untreated cancer patients. Responders (n = 314) showed significantly elevated activity of alkaline DNase as compared to untreated cancer patients (p < 0.001). While non-responders (n = 168) showed comparable activity with untreated cancer patients. Serum alkaline DNase activities were significantly elevated in responders as compared to non-responders (p < 0.001). Our clinical studies during follow-up of patients indicated that the variations in serum alkaline DNase activities in individual patients correlate closely with response to therapy. Serum alkaline DNase also appeared to be useful in predicting treatment response in the long-term follow-up of patients. Serum alkaline DNase was systematically examined as a possible indicator for recurrence in patients under complete remission. In conclusion, serum alkaline DNase may be useful as a treatment monitoring in patients with head and neck malignancies.

Combined evaluation of matrix metalloproteinases and their inhibitors has better clinical utility in oral cancer.

Background Oral cancer is a major health hazard worldwide with increasing incidence and mortality. Cervical lymph node metastasis is a major determinant of outcome in oral cancer. The matrix metalloproteinase (MMP) system is critically involved in invasion and metastasis. Assessment of MMPs and tissue inhibitors of MMPs (TIMPs) in certain combinations might have better clinical efficacy given their potential role in the metastatic process. Aim Plasma concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 in 50 controls and 75 oral cancer patients (nonmetastatic, n=54; metastatic, n=21) were evaluated to assess their investigative value and role in predicting the behavior of this malignancy. Methods The plasma concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 were quantified by ELISA. The best 2- and 3-marker combinations were calculated using the statistical software mROC. The diagnostic values for all the biomolecules as single markers and their combinations were estimated using the measures of diagnostic accuracy, i.e. the area under the ROC curve and the sensitivity and specificity at cutoff limits with the highest diagnostic accuracy and at the 95% limits of sensitivity and specificity, respectively. Results MMP-9, TIMP-1 and TIMP-2 were significantly elevated (p=0.000, p=0.013 and p=0.005, respectively) in oral cancer patients. MMP-9 emerged as the best single statistically significant marker in plasma for oral cancer detection. It showed an increase in diagnostic performance when tested in combination with MMP-2 and TIMP-2. The median plasma MMP-9 levels were elevated in both the metastatic and nonmetastatic groups compared with controls (p<0.004 and p<0.007, respectively). Conclusion The results indicated that plasma MMP and TIMP levels in relevant combinations may facilitate clinical decision-making for improved management of oral cancer patients and may provide important data for selecting patients for treatment with drugs that interfere with MMP and TIMP activities.

Prevalence of high-risk human papillomavirus type 16 and 18 in oral and cervical cancers in population from Gujarat, West India.

BACKGROUND Oral and cervical cancers are major malignancies in men and women, respectively, in India. This study evaluated occurrence of human papillomavirus (HPV) 16 and 18 infections in oral and cervical cancers to estimate HPV-associated burden of these cancers in the population from Gujarat, West India. METHODS A total of 97 malignant oral carcinoma tissues and 52 cervical carcinoma tissues were analyzed by type-specific PCR for the presence of HPV type 16 and 18 infections. RESULTS None of the oral cancer patients revealed the presence of HPV type 16 and 18 infection. In cervical cancer, 31 (59.6%) patients were infected with HPV 16 and 18. Of these 31 HPV-positive cervical cancer patients, 28 (90.3%) were infected with HPV 16 and 3 (9.7%) were infected with HPV 18. CONCLUSION The results suggested that HPV 16 and 18 do not play an important role in oral carcinogenesis in the population from Gujarat, West India. However, HPV 16 is highly prevalent in the cervical cancer patients, which may be considered for planning of prevention programs such as screening and vaccination in women from this region.

VEGFA isoforms play a vital role in oral cancer progression

Angiogenesis plays an important role in tumor growth and prognostication. A key angiogenesis stimulator is vascular endothelial growth factor (VEGF). The present investigation aimed to study contribution of VEGFA isoforms in oral cancer progression. Reverse transcription polymerase chain reaction and ELISA were employed to analyze tissue VEGFA isoforms and serum VEGF levels, respectively, in 109 oral cancer cases and 50 controls. VEGF183 and VEGF165 were significantly downregulated in malignant tissues as compared to adjacent normal tissues. VEGF183 and VEGF189 were significantly associated with tumor differentiation and tumor size. VEGF165 was significantly higher in recurrent early stage tumors. Serum VEGF levels were significantly higher in cases as compared to the controls and were associated with tumor differentiation. Serum VEGF levels were significantly higher in patients with recurrent advanced stage tumors. Further, patients with high levels of VEGF165 and serum VEGF levels had the worst prognosis. VEGFA isoform status and serum VEGF levels play a significant role in the progression as well as prognosis of oral cancer.

Recent candidate molecular markers: vitamin D signaling and apoptosis specific regulator of p53 (ASPP) in breast cancer.

Regardless of advances in treatment modalities with the invention of newer therapies, breast cancer remains a major health problem with respect to its diagnosis, treatment and management. This female malignancy with its tremendous heterogeneous nature is linked to high incidence and mortality rates, especially in developing region of the world. It is the malignancy composed of distinct biological subtypes with diverse clinical, pathological, molecular and genetic features as well as different therapeutic responsiveness and outcomes. This inconsistency can be partially overcome by finding novel molecular markers with biological significance. In recent years, newer technologies help us to indentify distinct biomarkers and increase our understanding of the molecular basis of breast cancer. However, certain issues need to be resolved that limit the application of gene expression profiling to current clinical practice. Despite the complex nature of gene expression patterns of cDNAs in microarrays, there are some innovative regulatory molecules and functional pathways that allow us to predict breast cancer behavior in the clinic and provide new targets for breast cancer treatment. This review describes the landscape of different molecular markers with particular spotlight on vitamin D signaling pathway and apoptotic specific protein of p53 (ASPP) family members in breast cancer.