PAIII prostate tumors express prostate specific antigen (PSA) in Lobund-Wistar rats

Prostate cancer has been modeled in various species, including dogs, mice, and rats. A common method involves the use of transplanted prostate cancer cell lines. The Lobund-Wistar (LW) rat model of prostate cancer allows for the use of models involving either autochthonous prostate cancer or transplantation of a cell line (PAIII), originally derived from a LW rat. The origin of autochthonous prostate tumors in the LW rat is unknown, though suspected to originate from the seminal vesicles. Likewise, the prostatic origin of the PAIII cell line is also uncertain. To determine if the PAIII cell line is derived from the prostate, subcutaneous PAIII tumors from LW rats underwent immunohistochemical labeling for prostate specific antigen (PSA), a prostate-specific serine protease. All 5 PAIII tumors demonstrated labeling for PSA, supporting a prostatic origin for the PAIII cell line.