## 3 Discussion  
Here, we developed the LM-GlycomeAtlas to visualize LMA-based glycemic profiling data obtained from FFPE sections of mouse tissues. The LM-GlycomeAtlas is the first database for LMA-based glycan data analysis, which is highlighted by the fact that many databases for MS-based  
Figure 4: PCA score plots for eight tissues: (**a**) pancreas, (**b**) heart (transverse section), (**c**) lung, (**d**) thymus, (**e**) skin, (**f**) stomach, (**g**) small intestine (ileum), and (**h**) colon. The region/sub-region names and number of the data correspond to those in the sample lists shown in Table 1.  
data of glycan structures and glycomic profiles are currently available [10; 11]. This tool is freely available under \"Resources\" \(\rightarrow\) \"Database: Glycomes\" \(\rightarrow\) \"LM-GlycomeAtlas\" in the GlyCosmos Portal ([[https://glycosmos.org](https://glycosmos.org)]([https://glycosmos.org](https://glycosmos.org))), which is the official web portal of the Japanese Society for Carbohydrate Research. Both the GlycomeAtlas and LM-GlycomeAtlas provide similar user interfaces from the same portal, allowing users to easily compare the MS-based and LMA-based tissue glycomic profiling data. In addition to visualization directly on the LM-GlycomeAtlas web page, the glycomic profiling data for nine mouse FFPE tissues associated with sample information can also be downloaded from the website in an Excel format file, allowing the use of the data off-line. Although the labeling efficiency depends on the number of the targeting functional groups (i.e., primary amines), the LMA-based glycomic profiles provide meaningful information on the characteristics in the glycan structures attached on glycoproteins. In the present LMD-LMA procedure (Figure 1), the preparation condition of the FFPE tissue sections may influence the resulting glycomic profiles; for example, the tertiary structure of tissue proteins, which determines accessible functional groups and glycans, varies depending on the conditions of tissue fixation (i.e., the type of fixative and incubation time). In addition, the conditions of the heat denaturation of the tissue fragments (i.e., the pH of the buffer and incubation time) have a potential impact on the sialylation status of the glycans, reflecting their affinity to sialic acid-binding lectins. Since the present dataset of nine mouse tissues was obtained using the unified procedure for all tissues (Table 2), all tissue glycemic profiles are comparable with each other. By comparing the glycemic profiles between sites and tissues (Figure 4), a lectin probe can be selected that is suitable for detecting the glycan structures that are relatively abundant in particular sites and tissues. The selected lectin probe can be used for affinity capturing to identify the glycan structures and carrier proteins by MS [12; 13; 14], and for histochemical analysis to elucidate which cells and sites express glycans of interest [7; 8; 15; 16; 17; 18]. The cell type-specific lectin will facilitate cell type-selective glycomic profiling of FFPE tissue sections as a staining probe, as described previously [19]. In this context, the present tissue glycomic profiling data will contribute to the in-depth analysis of protein glycosylation, facilitating the discovery of disease-related glycosylation alterations. Since the LM-GlycomeAtlas is a highly extensible application similar to the GlycomeAtlas [9], this atlas can be updated as more data are deposited, including those on mouse tissues other than the present nine tissues as \"Ver. 1.0.\" In fact, we have collected the glycemic profiling data for five organs, including the brain, liver, kidney, spleen, and testis, of 8-week-old male C57 BL/6] mice, in a similar manner as that used for the present nine tissues [8]. The type of tissue sources will also be expanded, including genetically modified and disease model animals, including mice.