Immunohistochemical expression and significance of MMP1 in oral squamous cell carcinoma in relation to tumour depth

Introduction. Oral squamous cell carcinoma (OSCC)
is a malignancy of stratified squamous epithelium,
beginning as an epithelial dysplasia and progressing
until the dysplastic epithelial cells break the basement
membranes (BM) and invade the underlying connective
tissue. It is estimated that over 90% of all oral neoplasms
are OSCCs. Matrix metalloproteinase-1 (MMP1) is
an enzyme that in humans is encoded by the MMP1
gene which causes degradation of the extracellular
matrix (ECM) and BM, and thus may play a key role
in development and local invasion of OSCC. It can
serve as a potential biomarker molecule for diagnosis,
treatment and prognostic evaluation. Tumour depth
(TD) is considered to be a more reliable feature, as
many studies have shown that the risk of metastasis
and spread to cervical lymph node (LN) increases with
an increase in TD. Materials and Methods. Forty-five
formalin-fixed, paraffin-embedded blocks of totally
excised OSCC collected pro- and retrospectively
were included in this study. Hematoxylin &
Eosin stain was performed for each block for
reassessment of histopathological examination. An
immunohistochemical (IHC) staining was performed
using anti-MMP1 monoclonal antibodies. Results.
The majority of the OSCC sample revealed TD of
more than 7 mm (57.78%), with a maximum registered
depth of 18 mm. Furthermore, the data demonstrated a
significant correlation between TD and cervical lymph
node metastasis. Immunohistochemically, the tumour cells mostly showed MMP1 overexpression in score 4
(55.56%). Statistically, the MMP1 showed significant
correlation with TD. Conclusion. A significant
correlation was seen regarding the expression of
MMP1with TD suggesting that degradation and
collagenolytic activity against collagens in carcinoma
tissue extract was associated with deeper invasion.