PCA

PCA or PCa may refer to:

Medicine and biology

Military and government

PCA3

Prostate cancer antigen 3 (PCA3, also referred to as DD3) is a gene that expresses a non-coding RNA. PCA3 is only expressed in human prostate tissue, and the gene is highly overexpressed in prostate cancer. Because of its restricted expression profile, the PCA3 RNA is useful as a tumor marker.

Use as biomarker

The most frequently used biomarker for prostate cancer today is the serum level of prostate-specific antigen (PSA), or derived measurements. However, since PSA is prostate-specific but not cancer-specific, it is an imperfect biomarker. For example, PSA can increase in older men with benign prostatic hyperplasia. Several new biomarkers are being investigated to improve the diagnosis of prostate cancer. Some of these can be measured in urine samples, and it is possible that a combination of several urinary biomarkers will replace PSA in the future.

Compared to serum PSA, PCA3 has a lower sensitivity but a higher specificity and a better positive and negative predictive value. It is independent of prostate volume, whereas PSA is not. It should be measured in the first portion of urine after prostate massage with digital rectal examination.

Alpha 21164

The Alpha 21164, also known by its code name, EV5, is a microprocessor developed and fabricated by Digital Equipment Corporation that implemented the Alpha instruction set architecture (ISA). It was introduced in January 1995, succeeding the Alpha 21064A as Digital's flagship microprocessor. It was succeeded by the Alpha 21264 in 1998.

History

First silicon of the Alpha 21164 was produced in February 1994, and the OpenVMS, Digital UNIX and Windows NT operating systems were successfully booted on it. It was sampled in late 1994 and was introduced in January 1995 at 266 MHz. A 300 MHz version was introduced in March 1995. The final Alpha 21164, a 333 MHz version, was announced on 2 October 1995, available in sample quantities. The Alpha 21164 was replaced by the Alpha 21164A as Digital's flagship microprocessor in 1996 when a 400 MHz version became available in volume quantities.

Users

Digital used the Alpha 21164 operating at various clock frequencies in their AlphaServer servers, AlphaStation workstations. Digital also used the Alpha 21164 in their Alpha VME 5/352 and Alpha VME 5/480 single board computers and AlphaPC 164 and AlphaPC 164LX motherboards. Alpha partner Cray Research used a 300 MHz Alpha 21164 in their T3E-600 supercomputer. Third parties such as DeskStation also built workstations using the Alpha 21164.