Pathologic features of the morphological continuum from normal fallopian tube epithelium to invasive serous carcinoma. Normal fallopian tube epithelium (FTE), containing both secretory (thick arrow) and ciliated (thin arrow) cells, is typically immunonegative for p53, -H2AX (a marker of DNA damage), and MIB1 (antibody against Ki67; a proliferation marker). The benign “p53 signature” is composed of a stretch of secretory cells exhibiting strong p53 expression and evidence of DNA damage (i.e., nuclear γ-H2AX foci), but showing no signs of proliferation. Upon progression to TIC, there is an acquisition of proliferative capacity, as evidenced by gain of MIB1 immunoreactivity. High levels of p53, -H2AX, and MIB1 typically persist after a TIC develops into invasive serous carcinoma.