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DISCUSS THE POTENTIAL VALUE OF SALIVA IN THE DETECTION OF
ORAL CANCER
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INTRODUCTION:
(Oral cavity cancers and the pharynx cancers are the sixth most common type of
cancers worldwide
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Amongst all the oral cancer cases 90% cancers are the squamous cell carcinoma
cases
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Amongst all the malignancies the oral cancer have one of the highest mortality
ratio with 45% death rate within the 5 years of diagnosis accredited to the late
diagnosis of the disease
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Also the
increasing number of oral cancers have been found to be revealed diagnostically
within the saliva
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The Oral
Cancer Foundation be certain that oral cancer is dangerous because many
patients develop secondary or primary tumour at an advanced stage
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ORAL CANCER EARLY DETECTION APPROACHES:
Histopathological assessment following biopsy of a tissue is the most consistent
diagnostic method
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But still the final
diagnosis can be done only with the biopsy of a tissue, but microscopic

examination is done when it’s already very late
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In recent times the use of toluidine blue staining to
identify oral cancerous lesions have arisen as a successful analyst for cancer
diagnosis
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Brush biopsy a non-invasive, chair-side
investigative technique can be used to identify pre-malignant and early cancerous
lesions, but still a positive biopsy of doubtful unusual lesions is a requirement
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So, none of these approaches are useful for using on a large scale to
screen suspected populations as they require equipment and training
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Nucleic acid and proteins associated to a tumour can be identified in saliva, urine,
plasma or other body fluids and can act as a molecular marker for early diagnosis
for cancer
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The basic to achieve this are: precise biomarkers of
diseased and healthy ones, a non-invasive methodology to identify the
biomarkers and the equipment to categorize those biomarkers
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3 major salivary glands and many other minor salivary glands secrete the saliva
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and
these several important functions are succeeded by the various components of

saliva such as water, inorganic compounds, protein and non-protein compounds,
lipids, polypeptides and hormones
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The diagnostic use of saliva was anticipated long back
and is also easily accessible, its collection is non-invasive, non-time-consuming,
does not require training, not expensive and also mass screening of a large
population samples can be done
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The saliva sample is most commonly used for follow
up or diagnosis of any systemic disease, also some altered levels of mRNA and
proteins in saliva can help in diagnosis and follow up for oral cancers
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TP53, micro satellite
instability and the presence of HPV and EBV genomic sequences are the DNA
markers; cytokeratin are applied for RNA identification and protein markers are
CD44, 19 fragments and telomerases
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Microsatellite biomarkers stand furthermost likely because they have effectively
identified cancer cells within saliva in 79% of oral cancer patients, but it needs
huge quantity of cancer DNA for testing and lacks in specificity, so it is not
practicable to use it on a large scale
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Also a salivary cellfree nucleic acid and proteins can be locally produced by cell necrosis, lysis or
apoptosis and trauma and also can be released by normal epithelial and/or
cancerous cells
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Furthermore, the increasing
evidence concern that cell-free nucleic acid and proteins are present in apoptotic
bodies, which defend them from degradation
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Salivary cell-free nucleic
acids and proteins

Serum derived

Locally produced

Normal salivary secretion
Passive diffusion
Active transport
Ultrafiltration through tight junctions
Outflow of crevicular fluid
Cell necrosis, lysis
Apoptosis
Trauma
Active release

POTENTIAL SALIVARY BIOMARKERS FOR DETECTION OF ORAL CANCERS:
About 100 possible OSCC salivary biomarkers are been described in the literature,
which is depended mostly on relating the levels in the OSCC patients to the levels
in a non-OSCC healthy individuals, and is done by applying molecular biology
experimental methods as described below
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1
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Protein or peptide

High performance liquid
chromatography (HPLC)
Enzyme linked immunosorbent
assay (ELISA)

Radio-immunoassay
Two-dimensional gel
electrophoresis (2DE), followed
by mass spectrotomy (MS)
Two-dimensional gel
electrophoresis and reversephase liquid chromatography,
followed by liquid
chromatography- tandem
mass spectrotomy
Matrix assisted laser
desorption/ ionization time- offlight mass spectrotomy
(MALDI- TOF MS)
2DE followed by MALDI- TOF
MS
3
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1
Hemopexin

CD59

Alpha amylase, zinc finger
protein 501 peptide

Transferrin

1
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Variability in the levels of potential OSCC salivary biomarkers in both noncancerous individuals and OSCC patients, suggest unknown confounding factors
3
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Validation in the presence of common oral inflammatory conditions
b
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New biomarkers are discovered which were present in saliva
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Though, some disputes
and challenges are needed to be fixed to make salivary biomarkers as a consistent,
highly sensitive and precise technique for a clinical use
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The understanding attained in the salivary biomarker research
for OSCCs can assist as a significant guidance for salivary diagnostics which
includes identification, validation and application of salivary biomarkers for
diagnosis of other types of cancer and also for checking non-cancerous commotion
of diseases
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