The following statements are made regarding the role of tumour microenvironment directly contributing to the metastatic process:

A. Hypoxia in primary tumours can induce the expression of VEGF and matrix metalloproteinases (MMPs) to promote metastasis.
B. Tumour-associated macrophages (TAMs) always inhibit metastasis through immune surveillance.
C. Cancer-associated fibroblasts (CAFs) provide structural support and secrete factors that promote metastasis.
D. The acidic pH of the tumour microenvironment impedes cancer cell migration.

Which one of the following options represents all correct statements?

Correct option is D

EXPLANATION-

Statement A  (Correct)  – Hypoxia in tumors can induce the expression of VEGF (vascular endothelial growth factor) and matrix metalloproteinases (MMPs), both of which contribute to angiogenesis and extracellular matrix degradation, facilitating metastasis.
Statement B (Incorrect) – Tumor-associated macrophages (TAMs) do not always inhibit metastasis. In fact, in many cancers, TAMs support tumor growth and metastasis by promoting angiogenesis, suppressing immune responses, and remodeling the extracellular matrix.
Statement C (Correct) – Cancer-associated fibroblasts (CAFs) provide structural support and secrete various cytokines and growth factors that enhance tumor progression and metastasis.
Statement D (Incorrect)  – The acidic pH of the tumor microenvironment actually promotes cancer cell migration and invasion, not impedes it.

So, the correct option is (d) A and C only