Immunoexpression of Metallothionein in Oral Squamous Cell Carcinoma

Metallothionein (MT) is a family of ubiquitous low molecular weight (7 kDa), intracellular (cytoplasmic/nuclear), cysteine rich proteins with high affinity for heavy metals, present in both normal cells and neoplastic cells. Increased expression of MT has been reported to be associated with poor prognosis in various tumours. The objectives of the present study were to compare the expression of MT in normal subjects and in patients with oral squamous cell carcinoma (OSCC), to correlate the expression of MT with respect to clinical staging of OSCC and to evaluate the expression of MT with respect to different histopathological grades of OSCC.

Thirty cases of OSCC were staged clinically and graded histopathologically. Immunohistochemical method was used to detect the expression of MT in OSCC. The scores obtained were documented and compared statistically.

MT immunoreactivity was noticed in all cases of OSCC. A statistically significant difference was observed in immunoreactivity of MT between the normal and OSCC, and in different histopathological grades of OSCC (p = 0.00001*). However, no statistical significance was found in a number of immunopositive cells in different clinical stages of OSCC (p = 0.7573).

The MT immunoexpression increased from low grade to high grade OSCC. Hence, increased expression of MT may be related to poor prognosis in patients with OSCC.