The patients with high microsatellite instability (MSI-H)/mismatch repair deficient (dMMR) tumors recently have been reported that can benefit from immunotherapy, and MSI can be used as a genetic instability of a tumor detection index. However, many studies have shown that there are many heterogeneous phenomena in patients with MSI tumors in terms of immunotherapy, prognosis and chemotherapy sensitivity. Here we mainly review the research results of MSI detection methods, the mechanisms of MSI occurrence and its relationship with related tumors, aiming to make a brief analysis of the current research status of MSI and provide comparable reference and guidance value for further research in this field.

As the process of methanol to hydrocarbons (MTH) is catalyzed by acid sites, the regulation of framework aluminum siting and acid distribution in a zeolite catalyst to enhance its performance in MTH is an important and challenging task. In this work, the regulation of framework aluminum siting in H-MCM-22 was achieved through boron incorporation; the relation between catalytic performance and acid distribution was investigated. The results illustrate that the distribution of framework aluminum and Bronsted acid sites among three types of pores in H-MCM-22 can be regulated through adjusting the content of boron incorporated during synthesis, due to the competitive occupancy of various framework T sites between boron and aluminum, whereas the textural properties and overall acid types and amounts are less influenced by boron incorporation. Incorporating a proper content of boron can concentrate the Bronsted acid sites in the sinusoidal channels rather than in the surface pockets and supercages. The acid sites located in the surface pockets and supercages are prone to carbonaceous deposition, whereas those acid sites in the sinusoidal channels are crucial for MTH in the steady reaction stage. Moreover, the acid sites in the sinusoidal channels are favorable to the olefin-based cycle that produces preferentially higher olefins. As a result, the incorporation of proper content of boron delivers the H-MCM-22 zeolite much greater stability and higher selectivity to higher olefins such as propene and butene in MTH than previously reported. These results help to clarify the relation between the catalytic performance of H-MCM-22 in MTH and its acid distribution and then bring forward an effective approach to develop better MTH catalysts by regulating the acid distribution.