It is a form of adenocarcinoma, that produces mucin. When the adenocarcinoma contains more than 50% signet rings it is referred to as a signet ring cell carcinoma. It is most often found in the glandular cells of the stomach, but it may develop in other areas of the body. e.g. the prostate,bladder, gallbladder,breast, colon,ovarian stroma and testis. It may also be seen in renal cell carcinoma. However many SRCC cases are rare. SRCC do not normally form in the lungs, stomach, or urinary bladder but there have been a few incidents where signet ring cell carcinoma has been reported in these areas. The SRCC in the stomach mainly appears in women and younger patients, while the SRCC of the urinary bladder occurs mainly in men around the ages of 38 to 83.
Some cases (not all) are inherited, and these cases are often caused by mutations in the CDH1 gene.
The mechanism of this malignant cancer is still unclear, however it has been found that a colon carcinoma cell known as HCC2998 causes an increase in differentiated tumor production.The reason for this increase is due to the active PI3K that were "converted to a signet ring carcinoma-like cells".
The pattern of metastases is different for gastric signet cell carcinoma than for intestinal-type gastric carcinoma. In cases where gastric signet cell carcinoma metastasizes, it tends to spread to peritoneal metastases, lymphatic permeation of the lungs, and to the ovaries, creating Krukenberg tumors.
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^ abMakino T, Tsujinaka T, Mishima H et al. (2006). "Primary signet-ring cell carcinoma of the colon and rectum: report of eight cases and review of 154 Japanese cases". Hepatogastroenterology53 (72): 845–9. PMID17153438.CS1 maint: Explicit use of et al. (link)