The phrase "a major challenge because" is correct and usable in written English.
It can be used to introduce a reason or explanation for why something is considered a significant difficulty or obstacle.
Example: "The project was delayed, which presented a major challenge because we had tight deadlines to meet."
Alternatives: "a significant obstacle due to" or "a considerable difficulty as a result of".
This is a major challenge because in the vast majority of cases, we do not know what the true positives and negatives are.
Clinical trials, however, have become a major challenge because of issues with trial endpoints.
Anastomotic leakage in colorectal surgery remains a major challenge because of its early and late consequences.
Structure determination of multidomain proteins remains a major challenge because of their dynamic and heterogeneous nature.
The oral delivery of hydrophobic drugs presents a major challenge because of the low aqueous solubility of such compounds.
The interpretation of microarray data remains a major challenge because of the complexity of the underlying biological networks.
The eradication of parthenium is a major challenge, primarily because of its epidemic proliferation, strong reproductive potential, hardiness, and competitiveness, apart from its wide ecological adoptability.
Translating from one language to another is hard, and creating a system that does it automatically is a major challenge, partly because there are just so many words, phrases and rules to deal with.
The dissection of the biology of breast cancer remains a major challenge, particularly because of the considerable interpatient and intrapatient molecular heterogeneity in tumor cells.
Despite the existence of numerous algorithms, the computational identification of IDPs still represents a major challenge, mainly because of the absence of a proper consensus definition on how to identify an IDP [ 3, 29– 33].
Despite the list of new and classical agents designed for the treatment of type II diabetes, such as thiazolidinediones, biguanides, meglitinides, or sulphonylureas is increasingly long, a major challenge remains because even using the more aggressive therapy, glycemic control in type II diabetic patients may still deteriorate.
