Predominant pattern of tumor infiltrating growth into the surrounding tissue. Infiltrating growth pattern was classified as follows: INFα: tumor shows expanding growth and a distinct border with the surrounding tissue (Figure1
A); INFγ: tumor shows infiltrating growth and an indistinct border with the surrounding tissue (Figure 1
C); INFβ: intermediate between INFγ and INFβ (Figure 1
B) (hematoxylin and eosin, ×40).