The phrase "are extensively established" is correct and usable in written English.
It can be used to describe something that has been firmly set up or widely recognized over a significant period of time.
Example: "The principles of democracy are extensively established in many countries around the world."
Alternatives: "are well established" or "are firmly established".
Crosstalk or reciprocal regulation between hormone-dependent pathways, including ERα- and AR-mediated signal transduction, and NF-κB signaling has been extensively established at multiple signaling nodes [43], [44], [45].
In the last decades, it has been extensively established that multicellular spheroids represent an efficient model to validate effects of drugs and treatments for human care applications.
Therefore it comes as no surprise that the approximate controllability for various control systems has been extensively established in the literature; see [3 8] and the references cited therein.
Given that the lack of P. falciparum-encoded microRNAs and microRNA processing machinery has been extensively established, we did not anticipate microRNA sponge roles for P. falciparum circRNAs [ 39, 40, 58].
The correlation of physiological sensitivity to insulin (vis-à-vis glycemic regulation) and longevity is extensively established, creating a justifiable gerontological interest on whether insulin sensitivity is causative, or even predictive, of some or all phenotypes of slowed senescence (including longevity).
Finite-memory nonlinear systems (FMNS) are extensively used in establishing a simple relationship between the output and input of complicated nonlinear systems.
Cell lines established from human tissues are extensively used to study human diseases and other conditions.
It has, in fact, been established that the majority of proteins found in urine are extensively degraded [27].
Cancer pain continues to be extensively undertreated, despite established guidelines.
All his books are extensively researched.
