PIK3CB是致癌基因，编码蛋白是PI3K的催化亚基P110-β；PI3K在产生磷酸肌醇3，4，5-三磷酸（PIP3）中起重要作用；PIP3作为一种关键的细胞信号通路（Akt-mTOR）的第二信使起作用。PIK3CB在由PTEN缺失驱动的肿瘤发生中起到关键作用并驱动PI3K信号传导。PIK3CB除了对PI3K/AKT通路的原癌基因的激活，还包括对生长和细胞代谢的影响，其中包括胰岛素信号转导。在HER2扩增和PIK3CA突变的癌症中，抑制PIK3CA后，PI3K信号通路可以通过PIK3CB重新激活。PIK3CB在多种癌症种发生扩增和激活突变。

PIK3CB, a catalytic subunit of PI3-kinase, is altered by amplification or mutation across a diverse range of cancer types. PIK3CB, also known as p110-β, is a catalytic subunit of PI3K that is important in creating phosphoinositol 3, 4, 5-trisphosphate (PIP3), which acts as a secondary messenger in key cellular signaling pathways such as AKT-mTOR. PIK3CB plays a critical role in tumorigenesis driven by loss of PTEN and drives PI3K signaling. Roles other than oncogenic activation of PI3K/AKT pathway have also been described for PIK3CB, including effects on growth and cell metabolism, including insulin signaling. In HER2-amplified and PIK3CA-mutant cancers, inhibition of PIK3CA can lead to reactivation of PI3K signaling through PIK3CB. Hence, combined inhibition of both isoforms is a promising therapeutic strategy that blocks pathway activation and leads to successful tumor regression.

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