Table 2

Altered subcellular localization of PCNA in EGFR-deficient papillomas

Papillomas were removed, fixed, sectioned, and immunohistochemically stained for PCNA as described in “Materials and Methods.” PCNA-labeled cells with nuclear or cytoplasmic (includes cells labeled in both the nucleus and cytoplasm) staining in both the basal and suprabasal cell compartments and total basal nuclei were counted in randomly selected regions of each tumor. PCNA-labeled cells were counted in five tumors per genotype in at least eight microscopic fields, and labeling indices were calculated in each PCNA-stained tumor. At least 200 basal cells were counted in each papilloma. Data are reported as mean ± SE. Statistical significance was determined using Student’s t test. The experiment is representative of two experiments that were performed.

GenotypeBasal labeling indexaSuprabasal labeling indexTotal labeling index
EGFR−/−25.3 ± 6.339.7 ± 7.619.8 ± 6.640.3 ± 7.445.2 ± 12.680.0 ± 14.8
EGFR+/+49.8 ± 6.1b19.7 ± 5.0b23.1 ± 5.29.9 ± 3.4b72.9 ± 10.629.6 ± 8.3b
  • a Labeling index reported as the number of PCNA-labeled cells per 100 basal cells.

  • b Value was significantly different from that of corresponding EGFR +/+ value (P ≤ 0.05 using a Student’s t test).