Expression of osteopontin (OPN) in salivary gland carcinomas has only been described in a few, small studies and with contradictory results.

Two studies have examined the OPN expression in salivary gland carcinoma. They have examined a total of 33 salivary gland cancers distributed on four different subtypes – and they had contradictory results .

Yet, till the current time there is no strong evidence to suggest that the level of expression in salivary gland carcinomas cannot be used as a differential diagnostic or prognostic marker. It would be interesting to examine the plasma osteopontin level in patients with salivary gland cancer.

Osteopontin could be a potential target for anti-cancer therapy in salivary gland cancer, but further knowledge about the behaviour of osteopontin post-transcriptionally and the role of the different specific integrin receptor subunit combinations are required.

References:

1- Coppola D, Szabo M, Boulware D, Muraca P, Alsarraj M, Chambers AF, et al. Correlation of osteopontin protein expression and pathological stage across a wide variety of tumor histologies. Clin Cancer Res 2004 Jan 1;10(1 Pt 1):184-90.

2-Darling MR, Gauthier M, Jackson-Boeters L, Daley TD, Chambers AF, Tuck AB. Osteopontin expression in salivary gland tumours. Oral Oncol 2006 Apr;42(4):363-9.

Osteopontin (OPN) - multifunctional cytokine and an adhesion (glyco)protein secreted by a variety of cells, has been found to be involved in many physiologic and pathologic processes, including cancer. OPN was reported to be important for tumor initiation and progression in liver, gastric, colorectal, lung cancer. There are also data showing the participation of OPN in pathogenesis of salivary gland cancer. The exact role of OPN in carcinogenesis is not fully clarified. Some recent reports indicate the role of OPN as master regulator of Epithelial-Mesenchymal Transition (Kothari et al., 2016). According to other authors high MMP-7 and OPN expressions serve as unfavorable prognostic factors for NSCLC (Sun et al., 2015)… You can find here also the reference for two recent studies in the field of salivary gland cancer and OPN. 

1. Bjørndal K, Larsen SR, Godballe C, Krogdahl A. Osteopontin expression in salivary gland carcinomas. J Oral Pathol Med. 2011 Jul;40(6):451-5. doi: 10.1111/j.1600-0714.2010.00964.x. Epub 2010 Oct 24.

2. Fok TC, Lapointe H, Tuck AB, Chambers AF, Jackson-Boeters L, Daley TD, Darling MR. Expression and localization of osteopontin, homing cell adhesion molecule/CD44, and integrin αvβ3 in mucoepidermoid carcinoma and acinic cell adenocarcinoma of salivary gland origin. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014 Sep;118(3):320-9. doi: 10.1016/j.oooo.2014.05.004. Epub 2014 May 20.

3. Sun Y, Li D, Lv XH, Hua SC, Han JC, Xu F, Li XD. Roles of osteopontin and matrix metalloproteinase-7 in occurrence, progression, and prognosis of nonsmall cell lung cancer. J Res Med Sci. 2015 Dec;20(12):1138-46. doi: 10.4103/1735-1995.172980.

4. Kothari AN, Arffa ML, Chang V, Blackwell RH, Syn WK, Zhang J, Mi Z, Kuo PC. Osteopontin-A Master Regulator of Epithelial-Mesenchymal Transition. J Clin Med. 2016 Mar 23;5(4). pii: E39. doi: 10.3390/jcm5040039.

Hi Jacenda,

Regarding your question on a role of Osteopontin (OPN) expression in salivary gland cancer progression, an answer might be found in a paper “Prognostic factors in malignant tumours of the salivary glands” by Paul Speight and William Barrett, published in 2009 in Brit J Oral Maxill Surg  Volume 47, Issue 8, Pages 587–593. Authors underlined that salivary gland tumours are a relatively rare group of lesions best managed in specialist centres. They review some of the factors that influence their prognosis. The exact role of OPN in carcinogenesis is not fully clarified.Yet, till the current time there is no strong evidence to suggest that the level of expression in salivary gland carcinomas cannot be used as a differential diagnostic or prognostic marker. Please keep in mind the critical point revealed, namely clinical stage is the most important, with large malignancies having a poor prognosis regardless of histological grade and other features such as perineural invasion. Even high grade neoplasms may do well when they are small. A helpful guide to the management of salivary cancers is the “4 cm” rule.

Best wishes,

Ilya