Immunohistochemical analysis of stromal fibrocytes and myofibroblasts to envision the invasion and lymph node metastasis in oral squamous cell carcinoma

BACKGROUND: Tumor cells work in close coordination with stromal elements from its stage of emergence to metastasis. The study was designed to assess the presence and distribution pattern of stromal fibrocytes and myofibroblasts in oral squamous cell carcinoma (OSCC). Possibility of using these stromal cells as a marker for invasion and lymphnode metastasis was evaluated. MATERIALS AND METHODS: A total of 40 cases of OSCC consisting twenty cases of each lymph node positive (pN+) and lymph node negative (pN0) samples and ten normal oral mucosa (NOM) tissues were subjected to double immunostaining using CD34 and alpha-smooth muscle actin (α-SMA) antibodies. Stained sections were evaluated semiquantitatively. RESULTS: CD34 fibrocytes were seen in 70% of NOM and none of OSCC samples. α-SMA myofibroblasts were seen in 80% of OSCC and none of NOM samples. A statistically significant difference was found in fibrocyte values (P < 0.001) and myofibroblast values (P < 0.001) between NOM and OSCC study samples. No statistical significance in myofibroblast values between pN0 and pN+ study groups; however, their distribution pattern appreciably varied. CONCLUSIONS: This study suggested that fibrocytes could be used as one of the markers for early invasion. Abrupt loss of fibrocytes at the transition zone toward carcinoma and statistical significance in their values supported this inference. Heterogeneity in the distribution pattern of myofibroblasts in tumor stroma indicates that this variability may predict the tumor behavior toward nodal metastasis rather than their mere presence or absence.