Recker F, Kwiatkowski M K, Pettersson K, Piironen T, Lümmen G, Huber A, Tscholl R
Urological Clinic, Kantonsspital Aarau, Switzerland.
Eur Urol. 1998;33(6):549-55. doi: 10.1159/000019654.
To determine whether the serum levels of total prostate-specific antigen (t-PSA), free PSA (f-PSA) and PSA complexed to alpha 1-antichymotrypsin (PSA-ACT) result from different expressions in various prostatic zones.
In a series of 127 consecutive men undergoing transurethral resection of the prostate (TURP) for BPH between May 1995 and February 1996, t-PSA, f-PSA (ProStatus, Wallac) and PSA-ACT were measured before and 3-4 months after surgery. Pre- and postoperative prostate volumes were measured by TRUS. Resected tissue was assumed to be the transition zone (TZ) while postoperative volume was defined as peripheral zone (including the central one) (CPZ). Pre- and postoperative serum PSA was related to pre- and postoperative volume and resected tissue to the difference between pre- and postoperative serum PSA, respectively. The serum PSA per 1 g tissue was calculated. Group I consisted of 96 historically proven BPH with no signs of inflammation, group II of 19 BPH patients with transurethral catheters inserted sometime prior to surgery to relieve urinary retention, and group III of 12 patients with incidental carcinomas.
In patients undergoing TURP without prior catheterization (group I) t-PSA (group I) declined from median 3.43 to 0.96 ng/ml after TURP by 72%, even though the prostate volume did so only by 44%, whereas the ratio free-to-total (f/t) PSA remained stable (median 24.9% pre- vs. 26.6% postoperatively). The TZ expressed approximately 2.7-fold more t-PSA than the remaining CPZ: median 0.14 vs. 0.052 ng/ml/g, respectively, and as to f-PSA it did so likewise: median 0.032 vs. 0.012 ng/ml/g, respectively. With transurethral catheterization prior to surgery (group II) the t-PSA density within whole prostate increased 1.4-fold as compared to this density without such catheterization: from median 0.089 (group I) to 0.13 ng/ml/g tissue, respectively (p < 0.007), and within the TZ alone 1.6-fold elevation from median 0.14 to 0.23 ng/ml/g, respectively (p < 0.02) was observed. In incidental carcinoma (group III) a reduced ratio of f/t PSA of 11.7% in the TZ as compared to 22.1% in the CPZ (22.1%) was observed.
In BPH both t-PSA and f-PSA are predominantly expressed within the TZ, which could help to improve the specificity of the PSA density in cancer detection by using the sum of the t-PSA densities of the TZ and CPZ: (0.14 ng/ml/g x TZ) + (0.052 ng/ml/g x CPZ). It is the first time that the supposed origin of the incidental carcinoma (from the TZ) is confirmed biochemically by a f/t PSA ratio exclusively reduced in the TZ but not in the CPZ. The post-TURP unchanged free-to-total ratio (26.6%) may be useful for the early detection of cancer in patients followed up after TURP.
确定血清总前列腺特异性抗原（t-PSA）、游离PSA（f-PSA）以及与α1-抗糜蛋白酶结合的PSA（PSA-ACT）水平是否源于前列腺各区域的不同表达。
在1995年5月至1996年2月期间，对127例因良性前列腺增生（BPH）接受经尿道前列腺切除术（TURP）的连续男性患者，在手术前及术后3 - 4个月测量t-PSA、f-PSA（ProStatus，Wallac）和PSA-ACT。术前和术后前列腺体积通过经直肠超声（TRUS）测量。切除的组织被认为是移行区（TZ），而术后体积定义为外周区（包括中央区）（CPZ）。术前和术后血清PSA分别与术前和术后体积以及切除组织与术前和术后血清PSA的差异相关。计算每克组织的血清PSA。第一组由96例经历史证实的无炎症迹象的BPH患者组成，第二组由19例在手术前某个时间插入经尿道导管以缓解尿潴留的BPH患者组成，第三组由12例偶然发现癌症的患者组成。
在未预先插管的接受TURP的患者（第一组）中，TURP后t-PSA（第一组）从中位数3.43 ng/ml降至0.96 ng/ml，下降了72%，尽管前列腺体积仅下降了44%，而游离与总PSA的比值（f/t）保持稳定（术前中位数24.9%，术后26.6%）。TZ表达的t-PSA比其余CPZ多约2.7倍：中位数分别为0.14 ng/ml/g和0.052 ng/ml/g，f-PSA也是如此：中位数分别为0.032 ng/ml/g和0.012 ng/ml/g。手术前进行经尿道插管（第二组），整个前列腺内的t-PSA密度与未进行此类插管时相比增加了1.4倍：分别从第一组的中位数0.089增至0.13 ng/ml/g组织（p < 0.007），仅在TZ内从中位数0.14增至0.23 ng/ml/g，升高了1.6倍（p < 0.02）。在偶然发现的癌症（第三组）中，观察到TZ内f/t PSA比值为11.7%，而CPZ内为22.1%。
在BPH中，t-PSA和f-PSA主要在TZ内表达，这有助于通过使用TZ和CPZ的t-PSA密度之和来提高PSA密度在癌症检测中的特异性：（0.14 ng/ml/g×TZ） + （0.052 ng/ml/g×CPZ）。这是首次通过仅在TZ而非CPZ中降低的f/t PSA比值从生化角度证实偶然发现的癌症（起源于TZ）的推测来源。TURP后游离与总PSA比值不变（26.6%）可能有助于对TURP后随访的患者进行癌症早期检测。
