MMP1 and neoplasm: When correlating MMP-1 expression between our two PTC groups, the invasive tumor group presented with statistically significantly increased MMP-1 expression in tumor cells (80.0% (67.5–90.0%) vs. 70.0% (45.0–85.0%); p = 0.049) and in adjacent non-tumorous-tissue cells (60.0% (50.0–80.0%) vs. 50.0% (37.5–65.0%); p = 0.029) of invasive PTC.