RETRACTED ARTICLE: Loss of pigment epithelium-derived factor: a novel mechanism for the development of endocrine resistance in breast cancer

Table 1 Pigment epithelium-derived factor expression in normal versus breast tumor tissue samples

Tissue sample	n	PEDF status	Intensity score
Recurrence tumors	28 (47.6%)^a	Positive	> 150
	31 (52.4%)^b	Negative	≤ 25
Primary tumors	40 (67.8%)^a	Positive	> 150
	19 (32.2%)^b	Negative	≤ 25
Endocrine-responsive tumors	125 (83.3%)^c	Positive	> 150
	25 (16.7%)^d	Negative	≤ 25
Normal tissue	5 (100%)	Positive	≥ 200
	0 (0%)	Negative	≤ 25

A total of 209 breast cancer patients were initially treated with tamoxifen and 59 patients developed recurrence disease after a mean follow-up of 93 months. Immunohistochemistry (IHC) staining was performed on tissue microarrays (TMAs) constructed from recurrence breast tumors (n = 59) and matched primary breast tumors (n = 59). Normal background breast tissue was also used for comparison. TMAs were also constructed from endocrine-responsive tumor tissues (n = 150). A semi-automated quantitative image analysis system (ACIS II) was used to quantitate the staining of the TMA slides. For IHC analysis, pigment epithelium-derived factor (PEDF) staining was quantified as an intensity score (scale 0 to 255). ^a P < 0.00003, number of PEDF-positive recurrence tumors versus PEDF-positive primary tumors. ^b P < 0.000001, number of PEDF-negative recurrence tumors versus PEDF-negative primary tumors. ^c P < 0.00008, number of PEDF-positive recurrence tumors versus PEDF-positive endocrine-responsive tumors. ^d P < 0.000001, number of PEDF-negative recurrence tumors versus PEDF-negative endocrine-responsive tumors.

ISSN: 1465-542X