In earlier studies, researchers focused on neutral mucin type and sulfomucin
When stained with AB 1 pH very few acini are stained showing presence of very few sulfomucins.
When the sections are stained with AF, it shows very low colour intensity, so the presence of trace amounts of sulfomucins is confirmed.
With AF-AB staining few acini are stained blue showing presence of sialomucins while very few are stained purple confirming the presence of very few sulfomucins.
In that also neutral are more and in acidic sialomucins are more than sulfomucins.
Few of the acini are negative for PAS staining which may contain enzymes or some of the sulfomucins which are PAS negative.
It shows presence of both types of acidic mucins but in that sulfomucins are present in very much trace amounts.
In normal gastrointestinal mucosa, sulfomucins
are present exclusively in the colon compared to the complete exclusion of the small intestine, where sialomucins are produced.
Glickman et al (8) evaluated multilayered epithelium in samples obtained from 17 patients and found that its glandular cells expressed neutral mucins, sialomucins, and sulfomucins
at rates comparable to Barrett esophagus (88%, 100%, and 71% of cases, respectively, versus 100%, 100%, and 76%, respectively).
Since phenylhydrazine blocks specially the aldehyde produced by neutral glycoprotein, only the aldehyde formed by sialomucins and sulfomucins
remain reactive to PAS (Pearse; Bancroft & Cook).
The study of the mucinous component of the neoplasm was performed using 2 stains: (1) the AB-PAS stain, which distinguishes between acid mucins stained blue by AB and neutral mucins stained magenta by PAS; and (2) the AB-HID stain, which differentiates sulfomucins
stained brownish by HID and sialomucins stained blue by AB.