Phosphatase and Tensin Homolog is also known as PTEN, it is a phosphates encoding gene. PTEN gene is located on the long arm of chromosome 10 at the position 23.3. PTEN was first discovered in 1997, and it is a tumour suppressor gene (Li & Sun 1997, Li et al. 1997, Steck et al. 1997) it helps to regulate cell division. They function as a lipid phosphates to regulate signal transduction pathways, such as the phosphoinositide 3-kinase (PI3k), protein kinase B (AKT) . The activity of its lipid phosphate can dephosphorylate the D3 from PIP3. PIP3 is a lipid product of PI3K ( Mahatma & Dixon, 1998). Cell proliferation and cell survival signals is mediated by PIP3. PTEN dephosphorylate PIP3 to inhibit the activity of AKT, however one of the role
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However it has been shown that some mutations in the PTEN can result in various clinical features such as the PTEN Hamartoma Tumor Syndrome (PHTS) and the Autism spectrum disorders (ASD). The syndromes that falls into the PHTS categories includes, Bannayan-Riley-Ruvalcaba syndrome (BRRS), Cowden syndrome (CS), and PTEN-Related Proteus syndrome (PS).
BRRS is a genetic condition resulted by a deletion or mutation of the PTEN gene. However more than 60% of all cases of BBRS are due to the mutation of the PTEN gene. BRRS can be detected in early childhood, the characteristic feature of this syndrome includes macrocephaly, noncancerous tumours and hamartomas. Furthermore this condition is very rare (Longy M, Coulon V, et al. 1998). BRRS associate with developmental delay and learning disability.
CS is a disorder that result in higher risk of developing different type of benign and malignant tumours such as breast thyroid and endometrium. However this condition has a similar characterises to BRRS. The developing tumour like growths for this CS is found on the skin and mucous membrane, nevertheless they can occur in other part of the body. Majority of the CS cases has resulted from mutation of the PTEN gene (Smith, Emily H. et al. …show more content…
It has been demonstrated that PTEN mutations in tumours are localised to exon 5, 7 or 8. In breast cancer it has been demonstrated that there are about 10-40% loss of heterozygosity at chromosome 10 the region which contain PTEN gene. It appears in some studies that mutation of PTEN occurs in advanced and metastatic breast cancer. Furthermore, it has been found that the size and the stage of the tumour has a correlation with the PTEN expression, in patients with decreased expression of PTEN the size of the tumour was lager or the stage of the tumour was advanced. In a study it demonstrated that patients with breast cancer and had a higher PTEN expression, the 2-year relapse free survival rate was higher than those with lower PTEN expression. Nonetheless, in vitro studies have demonstrated that there is a link between PTEN and oestrogen receptor, in the absence of oestrogen the oestrogen receptor are activated by PI3K and AKT. Therefor the inhibition of PI3K/AKT is reduced by decreasing the PTEN expression. However patients with higher PTEN expression has a greater respond to tamoxifen. In addition, breast cancer patients that has a positive expression of PTEN and oestrogen receptor are much likely to survive for
However it has been shown that some mutations in the PTEN can result in various clinical features such as the PTEN Hamartoma Tumor Syndrome (PHTS) and the Autism spectrum disorders (ASD). The syndromes that falls into the PHTS categories includes, Bannayan-Riley-Ruvalcaba syndrome (BRRS), Cowden syndrome (CS), and PTEN-Related Proteus syndrome (PS).
BRRS is a genetic condition resulted by a deletion or mutation of the PTEN gene. However more than 60% of all cases of BBRS are due to the mutation of the PTEN gene. BRRS can be detected in early childhood, the characteristic feature of this syndrome includes macrocephaly, noncancerous tumours and hamartomas. Furthermore this condition is very rare (Longy M, Coulon V, et al. 1998). BRRS associate with developmental delay and learning disability.
CS is a disorder that result in higher risk of developing different type of benign and malignant tumours such as breast thyroid and endometrium. However this condition has a similar characterises to BRRS. The developing tumour like growths for this CS is found on the skin and mucous membrane, nevertheless they can occur in other part of the body. Majority of the CS cases has resulted from mutation of the PTEN gene (Smith, Emily H. et al. …show more content…
It has been demonstrated that PTEN mutations in tumours are localised to exon 5, 7 or 8. In breast cancer it has been demonstrated that there are about 10-40% loss of heterozygosity at chromosome 10 the region which contain PTEN gene. It appears in some studies that mutation of PTEN occurs in advanced and metastatic breast cancer. Furthermore, it has been found that the size and the stage of the tumour has a correlation with the PTEN expression, in patients with decreased expression of PTEN the size of the tumour was lager or the stage of the tumour was advanced. In a study it demonstrated that patients with breast cancer and had a higher PTEN expression, the 2-year relapse free survival rate was higher than those with lower PTEN expression. Nonetheless, in vitro studies have demonstrated that there is a link between PTEN and oestrogen receptor, in the absence of oestrogen the oestrogen receptor are activated by PI3K and AKT. Therefor the inhibition of PI3K/AKT is reduced by decreasing the PTEN expression. However patients with higher PTEN expression has a greater respond to tamoxifen. In addition, breast cancer patients that has a positive expression of PTEN and oestrogen receptor are much likely to survive for