Table 1.

S100P in cancer

Basal cell carcinoma of the salivary gland	S100P is used for differentiating basal cell neoplasms from adenoid cystic carcinomas [93].
Breast Cancer	S100P is one of the markers of cancer initiation, is expressed in ductal hyperplasia, in lesions with high-risk of progression, in situ and invasive ductal carcinomas, and is associated with poor prognosis. Its expression correlates with ERBB2/Her2/neu, ER (estradiol) and P4 expression [94-102].
Cholagiocarcinoma	S100P expression is a strong indicator of the early stages of cholangiocarcinoma with increased expression correlating with progression from low to high grade biliary intraepithelial neoplasia (BilIN) [103], and is a sensitive biomarker for detecting cholangicarcinoma [70].
Cervical cancer	S100P is upregulated in all stages of cervical adenocarcinoma [104-107].
Colon cancer	S100P is highly expressed in non-dysplastic tissue from ulcerative colitis patients with high-grade dysplasia [108], and may be used to distinguish flat adenoma from normal mucosa [109,110]. The overexpression of S100P in colorectal cancer cells promotes metastasis [111], and acts as a potential prognostic biomarker [112].
Esophageal cancer	S100P is downregulated in esophageal squamous cell carcinoma [113,114].
Endometrial Cancer	S100P expression is higher in endometrial cancer than in normal endometrium and increases with tumor grade [38].
Gastric cancer	Immunohistochemical analysis of tissue microarray shows S100P expression in >75% of gastric cancers; its downregulation in gastric cancer cell lines leads to apoptosis and inhibition of colony-formation. In contrast, low expression of S100P is linked to poor patients’ outcome [115,116].
Hepatocellular carcinoma	S100P is a novel prognostic factor in HCC that can predict survival in patients with advanced tumor stage or early recurrences [117,118].
Lung cancer	S100P is one of five genes found consistently deregulated in meta-analysis of 12 cDNA array studies. Its expression is observed in early stages of non-small cell lung cancer (NSCLC) and lung adenocarcinoma, and with S100A2 and trypsinogens is predictive of metastatic progression and poor survival in NSCLC [119-122].
Melanoma	S100P, RAGE and ezrin are significantly higher in melanomas than in benign nevus pigmentosus, and metastatic melanoma in comparison to the primary tumor [123].
Oral cancer	S100P is one of the salivary biomarkers in oral squamous carcinoma that can detect cancer recurrence in patients in remission [74,124].
Ovarian cancer	High expression of S100P is correlated with shorter overall survival after chemotherapy [125,126]; conversely, this is also noted in clear cell adenocarcinoma of the ovary which express low levels of S100P [127].
Prostate cancer	S100P is expressed in only 18.5% of prostate cancers, and its expression is significantly lower in cancer than in normal prostate and benign prostate hyperplasia [11]. However, it is one of the highest expressed genes in the androgen – independent CWR22 prostate cancer xenografts [128,129]. Additionally, it correlates with metastatic progression of hormone refractory prostate cancer cells [130].
Pancreatic adenocarcinoma	S100P is expressed in the precursor lesions of pancreatic ductal adenocarcinoma (PDAC), as well as throughout all stages of PDAC development and progression, and is involved in growth and invasion of cancer cells [50,131-134].
Mucinous cystic neoplasms	S100P is expressed in pancreatic mucinous cystic neoplasms (MCN) [59,135].
Intraductal papillary mucinous tumors	Intraductal papillary mucinous tumors (IPMTs) in the pancreas are also expressing S100P [136,137].
Urothelial cancer	S100P is a diagnostic biomarker of urothelial cancer [138,139], and acts as a potential marker for distinguishing urothelial from squamous differentiation [140].