The phrase "has been markedly increasing" is correct and usable in written English.
You can use this phrase to describe something that has been increasing in an observable way or to a significant degree. For example, "The demand for renewable energy sources has been markedly increasing over the past decade."
But the incidence of board rejections because of low sales prices has been "markedly increasing".
Among NSCLC subtypes, adenocarcinoma (approximately consisting of 60 to 70% of all NSCLC), has been markedly increasing in incidence over recent years [ 1, 2].
The incidence of ductal carcinoma in situ (DCIS) has been markedly increasing during the past two decades, and now represents 25 30% of all mammographically detected breast cancers (Chen et al, 2009).
On the other hand, the anti-inflammatory cytokine IL-10 has been markedly increased under its treatment [86, 87].
Supporting our finding, CVD biomarker, CK-MB activity, has been markedly increased in the plasma of N-nitrosamines-treated rats (Table 1).
Recent exposure, in this case, as reflected by the blood lead level, remains a critically important measurement, but by expanding the tool chest of measurement methods to include measures of cumulative dose, the ability to understand the full expression of lead toxicity has been markedly increased.
A particular concern of those doing the survey were facilities for their higher education students, whose numbers have been markedly increasing.
With the increase of voltages, the capture frequency of protein into the nanopore has been markedly enhanced.
This can occur even when, for example, average recommended dietary allowances have not been trespassed significantly, and BMI has not been markedly increased, or even not at all.
In recent years, the diagnosis and treatment of ovarian cancers have improved, but the long-term survival rate, especially the survival rate for advanced cases, still has not been markedly increased.
