Some adult stem cells, such as spermatogonia, are referred to as unipotent stem cells because they function in the organism to generate only one cell type.

TLS Online TPP Program

#Id: 1476

#Unit 4. Cell Communication and Cell Signaling

Hypermethylation of CpG dinucleotides of TSG gene causes cancer and hypomethylation of CpG dinucleotides of proto-oncogenes causes cancer.

TLS Online TPP Program

#Id: 1477

#Unit 4. Cell Communication and Cell Signaling

Overexpression of anti-apoptotic genes or loss of proapoptotic genes promotes tumorigenesis. The pro-apoptotic gene p53 is frequently mutated in cancers.

TLS Online TPP Program

#Id: 1478

#Unit 4. Cell Communication and Cell Signaling

Loss of SWI/SNF function, just like loss of Rb function, can lead to overgrowth and cancer.

TLS Online TPP Program

#Id: 1479

#Unit 4. Cell Communication and Cell Signaling

Characterization of the disease-causing deletion showed that the absence of two miRNAs, miR-15-a and miR-16-1, causes chronic lymphocytic leukemia (CLL)

TLS Online TPP Program

#Id: 1480

#Unit 4. Cell Communication and Cell Signaling

The miRNAs miR-15-a and miR-16-1 act like tumor-suppressors; they normally inhibit cell proliferation, and their absence leads to cell growth.

TLS Online TPP Program

#Id: 1481

#Unit 4. Cell Communication and Cell Signaling

Let-7 miRNAs down-regulate the translation of Ras. Thus in the absence of the miRNAs, Ras is constitutively overproduced, contributing to tumorigenesis.